# Even or odd

Test whether an integer is even or odd.

There is more than one way to solve this task:

• Use the even and odd predicates, if the language provides them.
• Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
• Divide i by 2. The remainder equals 0 iff i is even. The remainder equals +1 or -1 iff i is odd.
• Use modular congruences:
• i ≡ 0 (mod 2) iff i is even.
• i ≡ 1 (mod 2) iff i is odd.

## 0815

```}:s:|=<:2:x~#:e:=/~%~<:20:~\$=<:73:x<:69:~\$~\$~<:20:~\$=^:o:<:65:
x<:76:=\$=\$~\$<:6E:~\$<:a:~\$^:s:}:o:<:6F:x<:64:x~\$~\$\$<:a:~\$^:s:```

## 11l

```F is_even(i)
R i % 2 == 0

F is_odd(i)
R i % 2 == 1```

## 6502 Assembly

```        .lf  evenodd6502.lst
.cr  6502
.tf  evenodd6502.obj,ap1
;------------------------------------------------------
; Even or Odd for the 6502 by barrym95838 2014.12.10
; Thanks to sbprojects.com for a very nice assembler!
; The target for this assembly is an Apple II with
;   mixed-case output capabilities.  Apple IIs like to
;   work in '+128' ascii, and this version is tailored
;   to that preference.
; Tested and verified on AppleWin 1.20.0.0
;------------------------------------------------------
; Constant Section
;
CharIn   =   \$fd0c      ;Specific to the Apple II
CharOut  =   \$fded      ;Specific to the Apple II
;------------------------------------------------------
; The main program
;
main    ldy  #sIntro-sbase
jsr  puts       ;Print Intro
loop    jsr  CharIn     ;Get a char from stdin
cmp  #\$83       ;Ctrl-C?
beq  done       ;  yes:  end program
jsr  CharOut    ;Echo char
ldy  #sOdd-sbase ;Pre-load odd string
lsr             ;LSB of char to carry flag
bcs  isodd
ldy  #sEven-sbase
isodd   jsr  puts       ;Print appropriate response
beq  loop       ;Always taken
; Output NUL-terminated string @ offset Y
;
puts    lda  sbase,y    ;Get string char
beq  done       ;Done if NUL
jsr  CharOut    ;Output the char
iny             ;Point to next char
bne  puts       ;Loop up to 255 times
;------------------------------------------------------
; String Constants (in '+128' ascii, Apple II style)
;
sbase:                  ;String base address
sIntro  .az     -"Hit any key (Ctrl-C to quit):",-#13
sEven   .az     -" is even.",-#13
sOdd    .az     -" is odd.",-#13
;------------------------------------------------------
.en```

## 68000 Assembly

### Non-Destructive

```BTST D0,#1
BNE isOdd
;else, is even.
```

### Destructive

```AND.B D0,#1
BNE isOdd
;else, is even.
```
```ROR.B D0,#1
BCS isOdd
;else, is even.
```
```ROXR.B D0,#1
BCS isOdd
;else, is even.
```
```LSR.B D0,#1
BCS isOdd
;else, is even.
```
```ASR.B D0,#1
BCS isOdd
;else, is even.
```

You can also use `BCLR`,`BSET`, and `BCHG` in the same way you use `BTST`, as all of them copy the affected bit to the zero flag. `BCLR`,`BSET`, and `BCHG` will change the value of that bit after the test, so keep that in mind.

## 8080 Assembly

The instruction that's doing all the work here is `rar`, which is a bitwise right rotate of the accumulator through the carry flag. That leaves the low bit in the carry flag, which will be set if odd and clear if even.

```CMDLIN:	equ	80h		; Location of CP/M command line argument
puts:	equ	9h		; Syscall to print a string
;;;	Check if number given on command line is even or odd
org	100h
lxi	h,CMDLIN	; Find length of argument
mov	a,m
add	l		; Look up last character (digit)
mov	l,a
mov	a,m		; Retrieve low digit
rar			; Rotate low bit into carry flag
mvi	c,puts		; Prepare to print string
lxi	d,odd		; If carry is set, then the number is odd
jc	5		; So print 'odd'
lxi	d,even		; Otherwise, the number is even
jmp 	5		; So print 'even'
even:	db	'Even\$'		; Strings
odd:	db	'Odd\$'```
Output:
```A>evenodd 0
Even
A>evenodd 1
Odd
A>evenodd 2
Even
A>evenodd 3141592653
Odd
A>```

## 8086 Assembly

### Non-Destructive

```test ax,1
jne isOdd
;else, is even
```

### Destructive

```and ax,1
jne isOdd
;else, is even
```
```ror ax,1
jc isOdd
;else, is even
```
```rcr ax,1
jc isOdd
;else, is even
```
```sar ax,1
jc isOdd
;else, is even
```
```shr ax,1
jc isOdd
;else, is even
```

The `DIV` instruction can also work, but using `DIV` to divide by 2 is a waste of time, since the shift and rotate commands above do it faster.

## 8th

The 'mod' method also works, but the bit method is fastest.

```: odd? \ n -- boolean
dup 1 n:band 1 n:= ;
: even? \ n -- boolean
odd? not ;
```

This could be shortened to:

```: even? \ n -- f
1 n:band not ;
: odd? \ n -- f
even? not ;
```

## AArch64 Assembly

Works with: as version Raspberry Pi 3B version Buster 64 bits
```/* ARM assembly AARCH64 Raspberry PI 3B and android arm 64 bits*/
/*  program oddEven64.s   */

/*******************************************/
/* Constantes file                         */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"

/*********************************/
/* Initialized data              */
/*********************************/
.data
sMessResultOdd:        .asciz " @ is odd (impair) \n"
sMessResultEven:       .asciz " @ is even (pair)  \n"
szCarriageReturn:      .asciz "\n"

/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
sZoneConv:        .skip 24
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main
main:                                 //entry of program

mov x0,#5
bl testOddEven
mov x0,#12
bl testOddEven
mov x0,#2021
bl testOddEven
100:                                  //standard end of the program
mov x0, #0                        //return code
mov x8, #EXIT                     //request to exit program
svc #0                            //perform the system call

/***************************************************/
/*     test if number is odd or even               */
/***************************************************/
// x0 contains à number
testOddEven:
stp x1,lr,[sp,-16]!       // save  registres
tst x0,#1                   //test bit 0 to one
beq 1f                      //if result are all zéro, go to even
ldr x1,qAdrsZoneConv        //else display odd message
bl conversion10             //call decimal conversion
ldr x1,qAdrsZoneConv        //insert value conversion in message
bl strInsertAtCharInc
bl affichageMess
b 100f
1:
bl conversion10             //call decimal conversion
ldr x1,qAdrsZoneConv        //insert conversion in message
bl strInsertAtCharInc
bl affichageMess
100:
ldp x1,lr,[sp],16         // restaur des  2 registres
ret
/********************************************************/
/*        File Include fonctions                        */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"```
Output:
``` 5 is odd (impair)
12 is even (pair)
2021 is odd (impair)
```

## ABAP

```cl_demo_output=>display(
VALUE string_table(
FOR i = -5 WHILE i < 6 (
COND string(
LET r = i MOD 2 IN
WHEN r = 0 THEN |{ i } is even|
ELSE |{ i } is odd|
)
)
)
).
```
Output:
```Table
-5 is odd
-4 is even
-3 is odd
-2 is even
-1 is odd
0 is even
1 is odd
2 is even
3 is odd
4 is even
5 is odd
```

## Action!

```PROC OddByAnd(INT v)
IF (v&1)=0 THEN
Print(" even")
ELSE
Print(" odd ")
FI
RETURN

PROC OddByMod(INT v)
;MOD doesn't work properly for negative numbers in Action!
IF v<0 THEN
v=-v
FI
IF v MOD 2=0 THEN
Print(" even")
ELSE
Print(" odd ")
FI
RETURN

PROC OddByDiv(INT v)
INT d
d=(v/2)*2
IF v=d THEN
Print(" even")
ELSE
Print(" odd ")
FI
RETURN

PROC Main()
INT i

FOR i=-4 TO 4
DO
PrintF("%I is",i)
OddByAnd(i)
OddByMod(i)
OddByDiv(i)
PutE()
OD
RETURN```
Output:
```-4 is even even even
-3 is odd  odd  odd
-2 is even even even
-1 is odd  odd  odd
0 is even even even
1 is odd  odd  odd
2 is even even even
3 is odd  odd  odd
4 is even even even
```

```-- Ada has bitwise operators in package Interfaces,
-- but they work with Interfaces.Unsigned_*** types only.
-- Use rem or mod for Integer types, and let the compiler
-- optimize it.
declare
N : Integer := 5;
begin
if N rem 2 = 0 then
Put_Line ("Even number");
elseif N rem 2 /= 0 then
Put_Line ("Odd number");
else
Put_Line ("Something went really wrong!");
end if;
end;
```

## Agda

```even : ℕ → Bool
odd  : ℕ → Bool

even zero    = true
even (suc n) = odd n

odd zero    = false
odd (suc n) = even n
```

## Aime

```if (x & 1) {
# x is odd
} else {
# x is even
}```

## ALGOL 68

Works with: ALGOL 68G version Any - tested with release 2.8.win32
```# Algol 68 has a standard operator: ODD which returns TRUE if its integer  #
# operand is odd and FALSE if it is even                                   #
# E.g.:                                                                    #

INT n;
print( ( "Enter an integer: " ) );
read( ( n ) );
print( ( whole( n, 0 ), " is ", IF ODD n THEN "odd" ELSE "even" FI, newline ) )```

## ALGOL-M

Because ALGOL-M lacks a built-in MOD operator or function and does not support bitwise operations on integers, the test is a bit cumbersome, but gets the job done.

```BEGIN

% RETURN 1 IF EVEN, OTHERWISE 0 %
INTEGER FUNCTION EVEN(I);
INTEGER I;
BEGIN
EVEN := 1 - (I - 2 * (I / 2));
END;

% TEST THE ROUTINE %
INTEGER K;
FOR K := 1 STEP 3 UNTIL 10 DO
WRITE(K," IS ", IF EVEN(K) = 1 THEN "EVEN" ELSE "ODD");

END```
Output:
```    1 IS ODD
4 IS EVEN
7 IS ODD
10 IS EVEN```

An alternate (but mathematically equivalent) coding, demonstrating the use of a conditional test as part of an assignment statement:

```% RETURN 1 IF EVEN, OTHERWISE 0 %
INTEGER FUNCTION EVEN(I);
INTEGER I;
BEGIN
EVEN := (IF I = 2 * (I / 2) THEN 1 ELSE 0);
END;```

## ALGOL W

```begin
% the Algol W standard procedure odd returns true if its integer  %
% parameter is odd, false if it is even                           %
for i := 1, 1702, 23, -26
do begin
write( i, " is ", if odd( i ) then "odd" else "even" )
end for_i
end.```
Output:
```             1   is odd
1702   is even
23   is odd
-26   is even
```

## AntLang

```odd: {x mod 2}
even: {1 - x mod 2}```

## APL

The easiest way is probably to use modulo.

```      2|28
0
2|37
1
```

So you can write a user-defined operator.

```     odd ← 2∘|
```

## AppleScript

```set L to {3, 2, 1, 0, -1, -2, -3}

set evens to {}
set odds to {}

repeat with x in L
if (x mod 2 = 0) then
set the end of evens to x's contents
else
set the end of odds to x's contents
end if
end repeat

return {even:evens, odd:odds}
```
Output:
```{even:{2, 0, -2}, odd:{3, 1, -1, -3}}
```

Or, packaging reusable functions that can serve as arguments to filter, partition etc (deriving even from mod, and odd from even):

```----------------------- EVEN OR ODD ------------------------

-- even :: Int -> Bool
on even(n)
0 = n mod 2
end even

-- odd :: Int -> Bool
on odd(n)
not even(n)
end odd

--------------------------- TEST ---------------------------
on run

partition(odd, enumFromTo(-6, 6))

--> {{-5, -3, -1, 1, 3, 5}, {-6, -4, -2, 0, 2, 4, 6}}
end run

-------------------- GENERICS FOR TEST ---------------------

-- enumFromTo :: Int -> Int -> [Int]
on enumFromTo(m, n)
if m ≤ n then
set lst to {}
repeat with i from m to n
set end of lst to i
end repeat
lst
else
{}
end if
end enumFromTo

-- partition :: (a -> Bool) -> [a] -> ([a], [a])
on partition(p, xs)
tell mReturn(p)
set {ys, zs} to {{}, {}}
repeat with x in xs
set v to contents of x
if |λ|(v) then
set end of ys to v
else
set end of zs to v
end if
end repeat
end tell
{ys, zs}
end partition

-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
-- 2nd class handler function lifted into 1st class script wrapper.
if script is class of f then
f
else
script
property |λ| : f
end script
end if
end mReturn
```
Output:
```{{-5, -3, -1, 1, 3, 5}, {-6, -4, -2, 0, 2, 4, 6}}
```

## Arendelle

```( input , "Please enter a number: " )

{ @input % 2 = 0 ,

"| @input | is even!"
,
"| @input | is odd!"
}```

## ARM Assembly

Works with: as version Raspberry Pi
```/* ARM assembly Raspberry PI  or android 32 bits */
/*  program oddEven.s   */

/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly
for the routine affichageMess conversion10
see at end of this program the instruction include */
/* for constantes see task include a file in arm assembly */
/************************************/
/* Constantes                       */
/************************************/
.include "../constantes.inc"

/*********************************/
/* Initialized data              */
/*********************************/
.data
sMessResultOdd:        .asciz " @  is odd (impair) \n"
sMessResultEven:       .asciz " @  is even (pair)  \n"
szCarriageReturn:   .asciz "\n"

/*********************************/
/* UnInitialized data            */
/*********************************/
.bss
sZoneConv:        .skip 24
/*********************************/
/*  code section                 */
/*********************************/
.text
.global main
main:                                 @ entry of program

mov r0,#5
bl testOddEven
mov r0,#12
bl testOddEven
mov r0,#2021
bl testOddEven
100:                                  @ standard end of the program
mov r0, #0                        @ return code
mov r7, #EXIT                     @ request to exit program
svc #0                            @ perform the system call

/***************************************************/
/*     test if number is odd or even               */
/***************************************************/
// r0 contains à number
testOddEven:
push {r2-r8,lr}             @ save  registers
tst r0,#1                   @ test bit 0 to one
beq 1f                      @ if result are all zéro, go to even
ldr r1,iAdrsZoneConv        @ else display odd message
bl conversion10             @ call decimal conversion
ldr r1,iAdrsZoneConv        @ insert value conversion in message
bl strInsertAtCharInc
bl affichageMess
b 100f
1:
bl conversion10             @ call decimal conversion
ldr r1,iAdrsZoneConv        @ insert conversion in message
bl strInsertAtCharInc
bl affichageMess
100:
pop {r2-r8,lr}             @ restaur registers
bx lr                      @ return
/***************************************************/
/*      ROUTINES INCLUDE                           */
/***************************************************/
.include "../affichage.inc"```

## ArnoldC

```LISTEN TO ME VERY CAREFULLY isOdd
I NEED YOUR CLOTHES YOUR BOOTS AND YOUR MOTORCYCLE n
GIVE THESE PEOPLE AIR
HEY CHRISTMAS TREE result
YOU SET US UP @I LIED
GET TO THE CHOPPER result
HERE IS MY INVITATION n
I LET HIM GO 2
ENOUGH TALK
I'LL BE BACK result
HASTA LA VISTA, BABY

LISTEN TO ME VERY CAREFULLY showParity
I NEED YOUR CLOTHES YOUR BOOTS AND YOUR MOTORCYCLE n
TALK TO THE HAND n
HEY CHRISTMAS TREE parity
YOU SET US UP @I LIED
GET YOUR A** TO MARS parity
DO IT NOW isOdd n
BECAUSE I'M GOING TO SAY PLEASE parity
TALK TO THE HAND "odd"
BULLS***
TALK TO THE HAND "even"
YOU HAVE NO RESPECT FOR LOGIC
TALK TO THE HAND ""
HASTA LA VISTA, BABY

IT'S SHOWTIME
DO IT NOW showParity 5
DO IT NOW showParity 6
DO IT NOW showParity -11
YOU HAVE BEEN TERMINATED```
Output:
```5
odd

6
even

-11
odd
```

## Arturo

```loop (neg 5)..5 [x][
if? even? x -> print [pad to :string x 4 ": even"]
else -> print [pad to :string x 4 ": odd"]
]
```
Output:
```  -5 : odd
-4 : even
-3 : odd
-2 : even
-1 : odd
0 : even
1 : odd
2 : even
3 : odd
4 : even
5 : odd```

## Asymptote

```for (int i = 1; i <= 10; ++i)  {
if (i % 2 == 0) {
write(string(i), " is even");
} else {
write(string(i), " is odd");
}
}
```

## AutoHotkey

Bitwise ops are probably most efficient:

```if ( int & 1 ){
; do odd stuff
}else{
; do even stuff
}
```

## AWK

```function isodd(x) {
return (x%2)!=0;
}

function iseven(x) {
return (x%2)==0;
}
```

## BaCon

```' Even or odd
OPTION MEMTYPE int
SPLIT ARGUMENT\$ BY " " TO arg\$ SIZE dim
n = IIF\$(dim < 2, 0, VAL(arg\$))
PRINT n, " is ", IIF\$(EVEN(n), "even", "odd")
```
Output:
```prompt\$ ./even-or-odd 42
42 is even
prompt\$ ./even-or-odd 41
41 is odd```

## BASIC

### Applesoft BASIC

```10 INPUT "ENTER A NUMBER: ";N
20 IF N/2 <> INT(N/2) THEN PRINT "THE NUMBER IS ODD":GOTO 40
30 PRINT "THE NUMBER IS EVEN"
40 END
```
Works with: Commodore BASIC version 2.0

### Commodore BASIC

Uses bitwise AND as suggested.

```10 rem determine if integer is even or odd
20 print "Enter an integer:";
30 input i%
35 print
40 eo\$="even"
50 if (i% and 1)=1 then eo\$="odd"
60 print "The number ";i%;"is ";eo\$;"."
```

### GW-BASIC

```10 INPUT "Enter a number: ", N
20 IF N MOD 2 = 1 THEN PRINT "It is odd." ELSE PRINT "It is even."
```

### IS-BASIC

```100 DEF ODD(X)=MOD(X,2)
110 INPUT PROMPT "Enter a number: ":X
120 IF ODD(X) THEN
130   PRINT X;"is odd."
140 ELSE
150   PRINT X;"is even."
160 END IF```

### Minimal BASIC

```10 REM Even or odd
20 PRINT "Enter an integer number";
30 INPUT N
40 IF N/2 <> INT(N/2) THEN 70
50 PRINT "The number is even."
60 GOTO 80
70 PRINT "The number is odd."
80 END
```

### QB64

NB: Line numbers are not required in this language. Further, because of the Int variable type used for input, floating point values will not be accepted by the program. 0 is a problem, though, as it returns "Even" in the code below, even though it is not mathematically an even value. For code brevity, the 0 problem is not addressed. Finally, No Even or Odd predicates exist in this language.

```'This is a comment line. It also could have been preceded with "Rem"

Dim i%          'This line is not necessary, but % strict casts
'as an Int (2 bytes). "As Int" could have been used instead.
Input "#? ", i% 'Prints "#? " as a prompt and waits
'for user input terminated by pressing [ENTER].

'Binary integers example
If i% And 1 Then 'Test whether the input value AND 1 is 0 (false) or 1 (true).
'There is no global or constant "True" or "False".
Print "Odd"  'Prints "Odd" if the above tested "true".
Else             'This could have been also been "ElseIf Not (i% And 1)"
Print "Even" 'Prints "Even in all other cases (Else)
'or if the logical inverse of the input value AND 1 tested
'"true" (ElseIf).
End If

'Modular congruence example
If i% Mod 2 Then
Print "Still Odd"
Else
Print "Still Even"
End If```

### Tiny BASIC

```10 PRINT "Enter a number:"
20 INPUT N
30 IF 2*(N/2) = N THEN GOTO 60
40 PRINT "It's odd."
50 END
60 PRINT "It's even."
```

### BASIC256

Works with: True BASIC
```for i = 1 to 10
if (i mod 2) then print i;" is odd" else print i;" is even"
next i
end```

### QBasic

Works with: QBasic version 1.1
Works with: QuickBasic version 4.5
Works with: QRun BASIC
```FOR i = 1 TO 10
IF i AND 1 THEN PRINT i; " is odd" ELSE PRINT i; " is even"
NEXT i
```

### True BASIC

Works with: BASIC256
```FOR i = 1 to 10
IF MOD(i, 2) = 0 THEN PRINT i; " is odd" ELSE PRINT i; " is even"
NEXT i
END
```

### XBasic

Works with: Windows XBasic
```PROGRAM	"Even/Odd"

DECLARE FUNCTION  Entry ()

FUNCTION  Entry ()
FOR i = 1 TO 10
IF (i MOD 2) THEN PRINT i;" is odd" ELSE PRINT i;" is even"
NEXT i
END FUNCTION

END PROGRAM
```

## Batch File

```@echo off
set /p i=Insert number:

::bitwise and
set /a "test1=%i%&1"

::divide last character by 2
set /a test2=%i:~-1%/2

::modulo
set /a test3=%i% %% 2

set test
pause>nul
```

## BBC BASIC

Solutions using AND or MOD are restricted to 32-bit integers, so an alternative solution is given which works with a larger range of values.

```      IF FNisodd%(14) PRINT "14 is odd" ELSE PRINT "14 is even"
IF FNisodd%(15) PRINT "15 is odd" ELSE PRINT "15 is even"
IF FNisodd#(9876543210#) PRINT "9876543210 is odd" ELSE PRINT "9876543210 is even"
IF FNisodd#(9876543211#) PRINT "9876543211 is odd" ELSE PRINT "9876543211 is even"
END

REM Works for -2^31 <= n% < 2^31
DEF FNisodd%(n%) = (n% AND 1) <> 0

REM Works for -2^53 <= n# <= 2^53
DEF FNisodd#(n#) = n# <> 2 * INT(n# / 2)
```
Output:
```14 is even
15 is odd
9876543210 is even
9876543211 is odd
```

## bc

There are no bitwise operations, so this solution compares a remainder with zero. Calculation of i % 2 only works when scale = 0.

```i = -3

/* Assumes that i is an integer. */
scale = 0
if (i % 2 == 0) "i is even
"
if (i % 2) "i is odd
"
```

```beads 1 program 'Even or odd'

calc main_init
loop across:[-10, -5, 10, 5] val:v
log "{v}\todd:{is_odd(v)}\teven:{is_even(v)}"```
Output:
```-10	odd:N	even:Y
-5	odd:Y	even:N
10	odd:N	even:Y
5	odd:Y	even:N
```

## Befunge

```&2%52**"E"+,@
```

Outputs E if even, O if odd.

## BQN

```odd ← 2⊸|

!0 ≡ odd 12
!1 ≡ odd 31```

## Bracmat

Not the simplest solution, but the cheapest if the number that must be tested has thousands of digits.

```( ( even
=
. @( !arg
:   ?
[-2
( 0
| 2
| 4
| 6
| 8
)
)
)
& (odd=.~(even\$!arg))
& ( eventest
=
.   out
\$ (!arg is (even\$!arg&|not) even)
)
& ( oddtest
=
.   out
\$ (!arg is (odd\$!arg&|not) odd)
)
& eventest\$5556
& oddtest\$5556
& eventest\$857234098750432987502398457089435
& oddtest\$857234098750432987502398457089435
)```
Output:
```5556 is even
5556 is not odd
857234098750432987502398457089435 is not even
857234098750432987502398457089435 is odd```

## Brainf***

Assumes that input characters are an ASCII representation of a valid integer. Output is input mod 2.

```,[>,----------] Read until newline
++<             Get a 2 and move into position
[->-[>+>>]>     Do
[+[-<+>]>+>>]   divmod
<<<<<]          magic
>[-]<++++++++   Clear and get an 8
[>++++++<-]     to get a 48
>[>+<-]>.       to get n % 2 to ASCII and print
```

If one need only determine rather than act on the parity of the input, the following is sufficient; it terminates either quickly or never.

```,[>,----------]<[--]
```

`2.%`

## C

Test by bitwise and'ing 1, works for any builtin integer type as long as it's 2's complement (it's always so nowadays):

```if (x & 1) {
/* x is odd */
} else {
/* or not */
}
```

If using long integer type from GMP (`mpz_t`), there are provided macros:

```mpz_t x;
...
if (mpz_even_p(x)) { /* x is even */ }
if (mpz_odd_p(x))  { /* x is odd */ }
```

The macros evaluate `x` more than once, so it should not be something with side effects.

## C#

```namespace RosettaCode
{
using System;

public static class EvenOrOdd
{
public static bool IsEvenBitwise(this int number)
{
return (number & 1) == 0;
}

public static bool IsOddBitwise(this int number)
{
return (number & 1) != 0;
}

public static bool IsEvenRemainder(this int number)
{
int remainder;
Math.DivRem(number, 2, out remainder);
return remainder == 0;
}

public static bool IsOddRemainder(this int number)
{
int remainder;
Math.DivRem(number, 2, out remainder);
return remainder != 0;
}

public static bool IsEvenModulo(this int number)
{
return (number % 2) == 0;
}

public static bool IsOddModulo(this int number)
{
return (number % 2) != 0;
}
}
public class Program
{
public static void Main()
{
int num = 26;               //Set this to any integer.
if (num.IsEvenBitwise())    //Replace this with any even function.
{
Console.Write("Even");
}
else
{
Console.Write("Odd");
}
//Prints "Even".
if (num.IsOddBitwise())    //Replace this with any odd function.
{
Console.Write("Odd");
}
else
{
Console.Write("Even");
}
//Prints "Even".
}
}
}
```

## C++

Test using the modulo operator, or use the C example from above.

```bool isOdd(int x)
{
return x % 2;
}

bool isEven(int x)
{
return !(x % 2);
}
```

A slightly more type-generic version, for C++11 and later. This should theoretically work for any type convertible to `int`:

```template < typename T >
constexpr inline bool isEven( const T& v )
{
return isEven( int( v ) );
}

template <>
constexpr inline bool isEven< int >( const int& v )
{
return (v & 1) == 0;
}

template < typename T >
constexpr inline bool isOdd( const T& v )
{
return !isEven(v);
}
```

## Clojure

Standard predicates:

```(if (even? some-var) (do-even-stuff))
(if (odd? some-var) (do-odd-stuff))
```

## COBOL

```       IF FUNCTION REM(Num, 2) = 0
DISPLAY Num " is even."
ELSE
DISPLAY Num " is odd."
END-IF
```

## CoffeeScript

```isEven = (x) -> !(x%2)
```

## ColdFusion

```function f(numeric n) {
return n mod 2?"odd":"even"
}
```

## Common Lisp

Standard predicates:

```(if (evenp some-var) (do-even-stuff))
(if (oddp some-other-var) (do-odd-stuff))
```

### Alternate solution

I use Allegro CL 10.1

```;; Project : Even or odd

(defun evenodd (nr)
(cond ((evenp nr) "even")
((oddp nr) "odd")))
(dotimes (n 10)
(if (< n 1) (terpri))
(if (< n 9) (format t "~a" " "))
(write(+ n 1)) (format t "~a" ": ")
(format t "~a" (evenodd (+ n 1))) (terpri))
```

Output:

```1: odd
2: even
3: odd
4: even
5: odd
6: even
7: odd
8: even
9: odd
10: even
```

## Component Pascal

BlackBox Component Builder

```MODULE EvenOdd;
IMPORT StdLog,Args,Strings;

PROCEDURE BitwiseOdd(i: INTEGER): BOOLEAN;
BEGIN
RETURN 0 IN BITS(i)
END BitwiseOdd;

PROCEDURE Odd(i: INTEGER): BOOLEAN;
BEGIN
RETURN (i MOD 2) # 0
END Odd;

PROCEDURE CongruenceOdd(i: INTEGER): BOOLEAN;
BEGIN
RETURN ((i -1) MOD 2) = 0
END CongruenceOdd;

PROCEDURE Do*;
VAR
p: Args.Params;
i,done,x: INTEGER;
BEGIN
Args.Get(p);
StdLog.String("Builtin function: ");StdLog.Ln;i := 0;
WHILE i < p.argc DO
Strings.StringToInt(p.args[i],x,done);
StdLog.String(p.args[i] + " is:> ");
IF ODD(x) THEN StdLog.String("odd") ELSE StdLog.String("even") END;
StdLog.Ln;INC(i)
END;
StdLog.String("Bitwise: ");StdLog.Ln;i:= 0;
WHILE i < p.argc DO
Strings.StringToInt(p.args[i],x,done);
StdLog.String(p.args[i] + " is:> ");
IF BitwiseOdd(x) THEN StdLog.String("odd") ELSE StdLog.String("even") END;
StdLog.Ln;INC(i)
END;
StdLog.String("Module: ");StdLog.Ln;i := 0;
WHILE i < p.argc DO
Strings.StringToInt(p.args[i],x,done);
StdLog.String(p.args[i] + " is:> ");
IF Odd(x) THEN StdLog.String("odd") ELSE StdLog.String("even") END;
StdLog.Ln;INC(i)
END;
StdLog.String("Congruences: ");StdLog.Ln;i := 0;
WHILE i < p.argc DO
Strings.StringToInt(p.args[i],x,done);
StdLog.String(p.args[i] + " is:> ");
IF CongruenceOdd(x) THEN StdLog.String("odd") ELSE StdLog.String("even") END;
StdLog.Ln;INC(i)
END;
END Do;
```

Execute: ^Q EvenOdd.Do 10 11 0 57 34 -23 -42~

Output:
```Builtin function:
10  is:> even
11  is:> odd
0  is:> even
57  is:> odd
34  is:> even
-23  is:> odd
-42 is:> even
Bitwise:
10  is:> even
11  is:> odd
0  is:> even
57  is:> odd
34  is:> even
-23  is:> odd
-42 is:> even
Module:
10  is:> even
11  is:> odd
0  is:> even
57  is:> odd
34  is:> even
-23  is:> odd
-42 is:> even
Congruences:
10  is:> even
11  is:> odd
0  is:> even
57  is:> odd
34  is:> even
-23  is:> odd
-42 is:> even
```

## Crystal

```#Using bitwise shift
def isEven_bShift(n)
n == ((n >> 1) << 1)
end
def isOdd_bShift(n)
n != ((n >> 1) << 1)
end
#Using modulo operator
def isEven_mod(n)
(n % 2) == 0
end
def isOdd_mod(n)
(n % 2) != 0
end
# Using bitwise "and"
def isEven_bAnd(n)
(n & 1) ==  0
end
def isOdd_bAnd(n)
(n & 1) != 0
end

puts isEven_bShift(7)
puts isOdd_bShift(7)

puts isEven_mod(12)
puts isOdd_mod(12)

puts isEven_bAnd(21)
puts isOdd_bAnd(21)
```
Output:
```false
true
true
false
false
true
```

## D

```void main() {
import std.stdio, std.bigint;

foreach (immutable i; -5 .. 6)
writeln(i, " ", i & 1, " ", i % 2, " ", i.BigInt % 2);
}
```
Output:
```-5 1 -1 -1
-4 0 0 0
-3 1 -1 -1
-2 0 0 0
-1 1 -1 -1
0 0 0 0
1 1 1 1
2 0 0 0
3 1 1 1
4 0 0 0
5 1 1 1```

## DCL

```\$! in DCL, for integers, the least significant bit determines the logical value, where 1 is true and 0 is false
\$
\$ i = -5
\$ loop1:
\$  if i then \$ write sys\$output i, " is odd"
\$  if .not. i then \$ write sys\$output i, " is even"
\$  i = i + 1
\$  if i .le. 6 then \$ goto loop1
```
Output:
```\$ @even_odd
-5 is odd
-4 is even
-3 is odd
-2 is even
-1 is odd
0 is even
1 is odd
2 is even
3 is odd
4 is even
5 is odd
6 is even```

## Delphi

```program EvenOdd;

{\$APPTYPE CONSOLE}

{\$R *.res}

uses
System.SysUtils;

procedure IsOdd(aValue: Integer);
var
Odd: Boolean;
begin
Odd :=  aValue and 1 <> 0;
Write(Format('%d is ', [aValue]));
if Odd then
Writeln('odd')
else
Writeln('even');
end;

var
i: Integer;
begin
for i := -5 to 10 do
IsOdd(i);

end.
```
Output:
```-5 is odd
-4 is even
-3 is odd
-2 is even
-1 is odd
0 is even
1 is odd
2 is even
3 is odd
4 is even
5 is odd
6 is even
7 is odd
8 is even
9 is odd
10 is even
```

## Déjà Vu

```even n:
= 0 % n 2

odd:
not even

!. odd 0
!. even 0
!. odd 7
!. even 7```
Output:
```false
true
true
false```

## Diego

```use_namespace(rosettacode)_me();

funct(isEven)_arg(i)_ret()_calc(i%2)_equals(0);

reset_namespace[];```

## DWScript

Predicate:

```var isOdd := Odd(i);
```

Bitwise and:

```var isOdd := (i and 1)<>0;
```

Modulo:

```var isOdd := (i mod 2)=1;
```

## EDSAC order code

This implementation uses the `C` (logical AND multiplier register with memory) order. It will cause the machine to print an E if the number stored at address θ+15 is even, or an O if it is odd. As an example, we shall test the number 37 (`P18D` in EDSAC encoding).

```[ Even or odd
===========

A program for the EDSAC

Determines whether the number stored at
address 15@ is even or odd, and prints
'E' or 'O' accordingly

Works with Initial Orders 2 ]

T56K   [ load point ]
GK     [ base address ]

O11@   [ print letter shift ]
T10@   [ clear accumulator ]
H15@   [ multiplier := n ]
C12@   [ acc +:= mult AND 1 ]
S12@   [ acc -:= 1 ]
G8@    [ branch on negative ]
O14@   [ print 'O' ]
ZF     [ halt ]
[ 8 ]  O13@   [ print 'E' ]
ZF     [ halt ]

[ 10 ] P0F    [ used to clear acc ]
[ 11 ] *F     [ letter shift character ]
[ 12 ] P0D    [ const: 1 ]
[ 13 ] EF     [ character 'E' ]
[ 14 ] OF     [ character 'O' ]
[ 15 ] P18D   [ number to test: 37 ]

EZPF   [ branch to load point ]```
Output:
`O`

## Eiffel

```--bit testing
if i.bit_and (1) = 0 then
-- i is even
end

--built-in bit testing (uses bit_and)
if i.bit_test (0) then
-- i is odd
end

--integer remainder (modulo)
if i \\ 2 = 0 then
-- i is even
end
```

## Elixir

```defmodule RC do
import Integer

def even_or_odd(n) when is_even(n), do: "#{n} is even"
def even_or_odd(n)                , do: "#{n} is odd"
# In second "def", the guard clauses of "is_odd(n)" is unnecessary.

# Another definition way
def even_or_odd2(n) do
if is_even(n), do: "#{n} is even", else: "#{n} is odd"
end
end

Enum.each(-2..3, fn n -> IO.puts RC.even_or_odd(n) end)
```
Output:
```-2 is even
-1 is odd
0 is even
1 is odd
2 is even
3 is odd
```

Other ways to test even-ness:

```rem(n,2) == 0
```

## Emacs Lisp

```(require 'cl-lib)

(defun even-or-odd-p (n)
(if (cl-evenp n) 'even 'odd))

(defun even-or-odd-p (n)
(if (zerop (% n 2)) 'even 'odd))

(message "%d is %s" 3 (even-or-oddp 3))
(message "%d is %s" 2 (even-or-oddp 2))
```
Output:
```3 is odd
2 is even
```

## Erlang

### Using Division by 2 Method

```%% Implemented by Arjun Sunel
-module(even_odd).
-export([main/0]).

main()->
test(8).

test(N) ->
if (N rem 2)==1 ->
io:format("odd\n");
true ->
io:format("even\n")
end.
```

### Using the least-significant bit method

``` %% Implemented by Arjun Sunel
-module(even_odd2).
-export([main/0]).

main()->
test(10).

test(N) ->
if (N band 1)==1 ->
io:format("odd\n");
true ->
io:format("even\n")
end.
```

## ERRE

```PROGRAM ODD_EVEN

! works for -2^15 <= n% < 2^15

FUNCTION ISODD%(N%)
ISODD%=(N% AND 1)<>0
END FUNCTION

! works for -2^38 <= n# <= 2^38
FUNCTION ISODD#(N#)
ISODD#=N#<>2*INT(N#/2)
END FUNCTION

BEGIN
IF ISODD%(14) THEN PRINT("14 is odd") ELSE PRINT("14 is even") END IF
IF ISODD%(15) THEN PRINT("15 is odd") ELSE PRINT("15 is even") END IF
IF ISODD#(9876543210) THEN PRINT("9876543210 is odd") ELSE PRINT("9876543210 is even") END IF
IF ISODD#(9876543211) THEN PRINT("9876543211 is odd") ELSE PRINT("9876543211 is even") END IF
END PROGRAM```
Output:
```14 is even
15 is odd
9876543210 is even
9876543211 is odd
```

## Euphoria

Using standard function

```include std/math.e

for i = 1 to 10 do
? {i, is_even(i)}
end for```
Output:
```{1,0}
{2,1}
{3,0}
{4,1}
{5,0}
{6,1}
{7,0}
{8,1}
{9,0}
{10,1}
```

## Excel

Use the MOD function

```=MOD(33;2)
=MOD(18;2)```
Output:
```1
0
```

Use the ISEVEN function, returns TRUE or FALSE

```=ISEVEN(33)
=ISEVEN(18)```
Output:
```FALSE
TRUE
```

Use the ISODD function, returns TRUE or FALSE

```=ISODD(33)
=ISODD(18)```
Output:
```TRUE
FALSE
```

## F#

Bitwise and:

```let isEven x =
x &&& 1 = 0
```

Modulo:

```let isEven x =
x % 2 = 0
```

## Factor

The math vocabulary provides even? and odd? predicates. This example runs at the listener, which already uses the math vocabulary.

```( scratchpad ) 20 even? .
t
( scratchpad ) 35 even? .
f
( scratchpad ) 20 odd? .
f
( scratchpad ) 35 odd? .
t
```

## Fish

This example assumes that the input command i returns an integer when one was inputted and that the user inputs a valid positive integer terminated by a newline.

```<v"Please enter a number:"a
>l0)?!vo     v          <                        v    o<
^      >i:a=?v>i:a=?v\$a*+^>"The number is even."ar>l0=?!^>
>      >2%0=?^"The number is odd."ar ^
```

The actual computation is the 2%0= part. The rest is either user interface or parsing input.

## Forth

```: odd?  ( n -- ? ) 1 and ;
: even? ( n -- ? ) odd? 0= ;

\ Every value not equal to zero is considered true. Only zero is considered false.
```

## Fortran

Please find the compilation and example run in the comments at the beginning of the FORTRAN 2008 source. Separating the bit 0 parity module from the main program enables reuse of the even and odd functions. Even and odd, with scalar and vector interfaces demonstrate the generic function capability of FORTRAN 90. Threading, stdin, and all-intrinsics are vestigial and have no influence here other than to confuse you.

```!-*- mode: compilation; default-directory: "/tmp/" -*-
!Compilation started at Tue May 21 20:22:56
!
!a=./f && make \$a && OMP_NUM_THREADS=2 \$a < unixdict.txt
!gfortran -std=f2008 -Wall -ffree-form -fall-intrinsics f.f08 -o f
! n     odd    even
!-6    F    T
!-5    T    F
!-4    F    T
!-3    T    F
!-2    F    T
!-1    T    F
! 0    F    T
! 1    T    F
! 2    F    T
! 3    T    F
! 4    F    T
! 5    T    F
! 6    F    T
! -6 -5 -4 -3 -2 -1  0  1  2  3  4  5  6       n
!  F  T  F  T  F  T  F  T  F  T  F  T  F     odd
!  T  F  T  F  T  F  T  F  T  F  T  F  T    even
!
!Compilation finished at Tue May 21 20:22:56

module bit0parity

interface odd
module procedure odd_scalar, odd_list
end interface

interface even
module procedure even_scalar, even_list
end interface

contains

logical function odd_scalar(a)
implicit none
integer, intent(in) :: a
odd_scalar = btest(a, 0)
end function odd_scalar

logical function even_scalar(a)
implicit none
integer, intent(in) :: a
even_scalar = .not. odd_scalar(a)
end function even_scalar

function odd_list(a) result(rv)
implicit none
integer, dimension(:), intent(in) :: a
logical, dimension(size(a)) :: rv
rv = btest(a, 0)
end function odd_list

function even_list(a) result(rv)
implicit none
integer, dimension(:), intent(in) :: a
logical, dimension(size(a)) :: rv
rv = .not. odd_list(a)
end function even_list

end module bit0parity

program oe
use bit0parity
implicit none
integer :: i
integer, dimension(13) :: j
write(6,'(a2,2a8)') 'n', 'odd', 'even'
write(6, '(i2,2l5)') (i, odd_scalar(i), even_scalar(i), i=-6,6)
do i=-6, 6
j(i+7) = i
end do
write(6, '((13i3),a8/(13l3),a8/(13l3),a8)') j, 'n', odd(j), 'odd', even(j), 'even'
end program oe
```

## FreeBASIC

```' FB 1.05.0 Win64

Dim n As Integer

Do
Print "Enter an integer or 0 to finish : ";
Input "", n
If n = 0 Then
Exit Do
ElseIf n Mod 2 = 0 Then
Print "Your number is even"
Print
Else
Print "Your number is odd"
Print
End if
Loop

End
```

## Frink

```isEven[x is isInteger] := getBit[x,0] == 0
isOdd[x is isInteger] := getBit[x,0] == 1```

## Futhark

 This example is incorrect. Please fix the code and remove this message.Details: Futhark's syntax has changed, so this example will not compile
```fun main(x: int): bool = (x & 1) == 0
```

## Fōrmulæ

Fōrmulæ programs are not textual, visualization/edition of programs is done showing/manipulating structures but not text. Moreover, there can be multiple visual representations of the same program. Even though it is possible to have textual representation —i.e. XML, JSON— they are intended for storage and transfer purposes more than visualization and edition.

Programs in Fōrmulæ are created/edited online in its website, However they run on execution servers. By default remote servers are used, but they are limited in memory and processing power, since they are intended for demonstration and casual use. A local server can be downloaded and installed, it has no limitations (it runs in your own computer). Because of that, example programs can be fully visualized and edited, but some of them will not run if they require a moderate or heavy computation/memory resources, and no local server is being used.

In this page you can see the program(s) related to this task and their results.

## Gambas

```Public Sub Form_Open()
Dim sAnswer, sMessage As String

sAnswer = InputBox("Input an integer", "Odd or even")

If Odd(Val(sAnswer)) Then sMessage = "' is an odd number"
If Even(Val(sAnswer)) Then sMessage = "' is an even number"
Else
sMessage = "' does not compute!!"
Endif

Print "'" & sAnswer & sMessage

End
```

Output:

```'25' is an odd number
'100' is an even number
'Fred' does not compute!!
```

## GAP

```IsEvenInt(n);
IsOddInt(n);
```

## Genie

Using bitwise AND of the zero-bit.

```[indent = 4]
/*
Even or odd, in Genie
valac even_or_odd.gs
*/

def parity(n:int):bool
return ((n & 1) == 0)

def show_parity(n:int):void
print "%d is %s", n, parity(n) ? "even" : "odd"

init
show_parity(0)
show_parity(1)
show_parity(2)
show_parity(-2)
show_parity(-1)```
Output:
```prompt\$ valac even_or_odd.gs
prompt\$ ./even_or_odd
0 is even
1 is odd
2 is even
-2 is even
-1 is odd```

## Go

```package main

import (
"fmt"
"math/big"
)

func main() {
test(-2)
test(-1)
test(0)
test(1)
test(2)
testBig("-222222222222222222222222222222222222")
testBig("-1")
testBig("0")
testBig("1")
testBig("222222222222222222222222222222222222")
}

func test(n int) {
fmt.Printf("Testing integer %3d:  ", n)
// & 1 is a good way to test
if n&1 == 0 {
fmt.Print("even ")
} else {
fmt.Print(" odd ")
}
// Careful when using %: negative n % 2 returns -1.  So, the code below
// works, but can be broken by someone thinking they can reverse the
// test by testing n % 2 == 1.  The valid reverse test is n % 2 != 0.
if n%2 == 0 {
fmt.Println("even")
} else {
fmt.Println(" odd")
}
}

func testBig(s string) {
b, _ := new(big.Int).SetString(s, 10)
fmt.Printf("Testing big integer %v:  ", b)
// the Bit function is the only sensible test for big ints.
if b.Bit(0) == 0 {
fmt.Println("even")
} else {
fmt.Println("odd")
}
}
```
Output:
```Testing integer  -2:  even even
Testing integer  -1:   odd  odd
Testing integer   0:  even even
Testing integer   1:   odd  odd
Testing integer   2:  even even
Testing big integer -222222222222222222222222222222222222:  even
Testing big integer -1:  odd
Testing big integer 0:  even
Testing big integer 1:  odd
Testing big integer 222222222222222222222222222222222222:  even
```

## Groovy

Solution:

```def isOdd = { int i -> (i & 1) as boolean }
def isEven = {int i -> ! isOdd(i) }
```

Test:

```1.step(20, 2) { assert isOdd(it) }

50.step(-50, -2) { assert isEven(it) }
```

`even` and `odd` functions are already included in the standard Prelude.

```Prelude> even 5
False
Prelude> even 42
True
Prelude> odd 5
True
Prelude> odd 42
False
```

Where even is derived from rem, and odd is derived from even:

```import Prelude hiding (even, odd)

even, odd
:: (Integral a)
=> a -> Bool
even = (0 ==) . (`rem` 2)

odd = not . even

main :: IO ()
main = print (even <\$> [0 .. 9])
```
Output:
`[True,False,True,False,True,False,True,False,True,False]`

## Hoon

```|=  n=@ud
?:  =((mod n 2) 0)
"even"
"odd"```

## Icon and Unicon

One way is to check the remainder:

```procedure isEven(n)
return n%2 = 0
end
```

## J

Modulo:

```   2 | 2 3 5 7
0 1 1 1
2|2 3 5 7 + (2^89x)-1
1 0 0 0
```

Remainder:

```   (= <.&.-:) 2 3 5 7
1 0 0 0
(= <.&.-:) 2 3 5 7+(2^89x)-1
0 1 1 1
```

Last bit in bit representation:

```   {:"1@#: 2 3 5 7
0 1 1 1
{:"1@#: 2 3 5 7+(2^89x)-1
1 0 0 0
```

Bitwise and:

```   1 (17 b.) 2 3 5 7
0 1 1 1
```

Note: as a general rule, the simplest expressions in J should be preferred over more complex approaches.

## Java

Bitwise and:

```public static boolean isEven(int i){
return (i & 1) == 0;
}
```

Modulo:

```public static boolean isEven(int i){
return (i % 2) == 0;
}
```

Arbitrary precision bitwise:

```public static boolean isEven(BigInteger i){
return i.and(BigInteger.ONE).equals(BigInteger.ZERO);
}
```

Arbitrary precision bit test (even works for negative numbers because of the way `BigInteger` represents the bits of numbers):

```public static boolean isEven(BigInteger i){
return !i.testBit(0);
}
```

Arbitrary precision modulo:

```public static boolean isEven(BigInteger i){
return i.mod(BigInteger.valueOf(2)).equals(BigInteger.ZERO);
}
```

## JavaScript

### ES5

Bitwise:

```function isEven( i ) {
return (i & 1) === 0;
}
```

Modulo:

```function isEven( i ) {
return i % 2 === 0;
}

// Alternative
function isEven( i ) {
return !(i % 2);
}
```

### ES6

Lambda:

```// EMCAScript 6
const isEven = x => !(x % 2)
```

or, avoiding type coercion:

```(() => {
'use strict';

// even : Integral a => a -> Bool
const even = x => (x % 2) === 0;

// odd : Integral a => a -> Bool
const odd = x => !even(x);

// TEST ----------------------------------------
// range :: Int -> Int -> [Int]
const range = (m, n) =>
Array.from({
length: Math.floor(n - m) + 1
}, (_, i) => m + i);

// show :: a -> String
const show = JSON.stringify;

// xs :: [Int]
const xs = range(-6, 6);

return show([xs.filter(even), xs.filter(odd)]);
})();
```
Output:
`[[-6,-4,-2,0,2,4,6],[-5,-3,-1,1,3,5]]`

## jq

In practice, to test whether an integer, i, is even or odd in jq, one would typically use: i % 2

For example, if it were necessary to have a strictly boolean function that would test if its input is an even integer, one could define:

`def is_even: type == "number" and floor == 0 and . % 2 == 0;`

The check that the floor is 0 is necessary as % is defined on floating point numbers.

"is_odd" could be similarly defined:

`def is_odd: type == "number" and floor == 0 and . % 2 == 1;`

## Jsish

Using bitwise and of low bit.

```#!/usr/bin/env jsish
/* Even or Odd, in Jsish */
function isEven(n:number):boolean { return (n & 1) === 0; }

provide('isEven', 1);

if (Interp.conf('unitTest')) {
;    isEven(0);
;    isEven(1);
;    isEven(2);
;    isEven(-13);
}

/*
=!EXPECTSTART!=
isEven(0) ==> true
isEven(1) ==> false
isEven(2) ==> true
isEven(-13) ==> false
=!EXPECTEND!=
*/
```
Output:
```\$ jsish --U isEven.jsi
isEven(0) ==> true
isEven(1) ==> false
isEven(2) ==> true
isEven(-13) ==> false```

## Julia

Built-in functions:

```iseven(i), isodd(i)
```

## K

The following implementation uses the modulo of division by 2

```oddp: {:[x!2;1;0]} /Returns 1 if arg. is odd
evenp: {~oddp[x]}  /Returns 1 if arg. is even

Examples:
oddp 32
0
evenp 32
1```

## Klingphix

```( -5 5 ) [
dup print " " print 2 mod ( ["Odd"] ["Even"] ) if print nl
] for

" " input```
Output:
```-5 Odd
-4 Even
-3 Odd
-2 Even
-1 Odd
0 Even
1 Odd
2 Even
3 Odd
4 Even
5 Odd```

## Kotlin

```// version 1.0.5-2

fun main(args: Array<String>) {
while (true) {
print("Enter an integer or 0 to finish : ")
val n = readLine()!!.toInt()
when {
n == 0     -> return
n % 2 == 0 -> println("Your number is even")
else       -> println("Your number is odd")
}
}
}
```

## Lambdatalk

```{def is_odd {lambda {:i} {= {% :i 2} 1}}}
-> is_odd

{def is_even {lambda {:i} {= {% :i 2} 0}}}
-> is_even

{is_odd 2}
-> false

{is_even 2}
-> true
```

## L++

```(defn bool isEven (int x) (return (% x 2)))
```

## LabVIEW

Using bitwise And
This image is a VI Snippet, an executable image of LabVIEW code. The LabVIEW version is shown on the top-right hand corner. You can download it, then drag-and-drop it onto the LabVIEW block diagram from a file browser, and it will appear as runnable, editable code. ## Lang5

```: even?  2 % not ;
: odd?  2 % ;
1 even? .   # 0
1 odd? .    # 1```

## Lasso

```define isoddoreven(i::integer) => {
#i % 2 ? return 'odd'
return 'even'
}
isoddoreven(12)
```

## LC3 Assembly

Prints EVEN if the number stored in NUM is even, otherwise ODD.

```      .ORIG      0x3000

LD         R0,NUM
AND        R1,R0,1
BRZ        EVEN

LEA        R0,ODD
BRNZP      DISP

EVEN  LEA        R0,EVN

DISP  PUTS

HALT

NUM   .FILL      0x1C

EVN   .STRINGZ   "EVEN\n"
ODD   .STRINGZ   "ODD\n"

.END```

## Liberty BASIC

```n=12

if n mod 2 = 0 then print "even" else print "odd"```

## Lingo

```on even (n)
return n mod 2 = 0
end

on odd (n)
return n mode 2 <> 0
end```

## Little Man Computer

Runs in Peter Higginson's simulator, to allow comments. Does not use his other extensions to the language.

LMC has no division instruction. To divide by 2 we could use repeated subtraction:

```// Input number; output its residue mod 2
INP        // read input into acc
BRZ write  // input = 0 is special case
loop   SUB k2     // keep subtracting 2 from acc
BRZ write  // if acc = 0, input is even
BRP loop   // if acc > 0, loop back
// (BRP branches if acc >= 0, but we've dealt with acc = 0)
LDA k1     // if acc < 0, input is odd
write  OUT        // output 0 or 1
HLT        // halt
k1     DAT 1      // constant 1
k2     DAT 2      // constant 2
// end```

The above program might need 500 subtractions before it found the result. To speed things up we could use something along the following lines.

```// Input number; output its residue mod 2
INP          // read input into accumulator
loop1    STA save_acc // save accumulator (see note below)
SUB k128     // keep subtracting 128 until acc < 0
BRP loop1
LDA save_acc // save_acc holds a number in range 0..127
loop2    STA save_acc
SUB k16      // keep subtracting 16 until acc < 0
BRP loop2
LDA save_acc // save_acc holds a number in range 0..15
loop3    STA save_acc
SUB k2       // keep subtracting 2 until acc < 0
BRP loop3
LDA save_acc // save_acc holds 0 or 1, the result
write    OUT          // output result
HLT
k2       DAT 2
k16      DAT 16
k128     DAT 128
save_acc DAT
// end```

Note: LMC, in its original form, does not support negative numbers. If the accumulator contains a number X, and a number Y > X is subtracted, then the negative flag is set and the value in the accumulator becomes undefined. So we can't assume that adding Y back to the accumulator will restore the value of X. If we want to use X again, we need to save it in RAM before doing the subtraction.

## LiveCode

```function odd n
return (n bitand 1) = 1
end odd

function notEven n
return (n mod 2) = 1
end notEven```

## LLVM

```; This is not strictly LLVM, as it uses the C library function "printf".
; LLVM does not provide a way to print values, so the alternative would be
; to just load the string into memory, and that would be boring.

; Additional comments have been inserted, as well as changes made from the output produced by clang such as putting more meaningful labels for the jumps

;--- The declarations for the external C functions
declare i32 @printf(i8*, ...)

\$"EVEN_STR" = comdat any
\$"ODD_STR" = comdat any

@"EVEN_STR" = linkonce_odr unnamed_addr constant [12 x i8] c"%d is even\0A\00", comdat, align 1
@"ODD_STR" = linkonce_odr unnamed_addr constant [11 x i8] c"%d is odd\0A\00", comdat, align 1

; Function Attrs: noinline nounwind optnone uwtable
define i32 @main() #0 {
%1 = alloca i32, align 4          ;-- allocate i
store i32 0, i32* %1, align 4     ;-- store 0 in i
br label %loop

loop:
%2 = load i32, i32* %1, align 4   ;-- load i
%3 = icmp ult i32 %2, 4           ;-- i < 4
br i1 %3, label %loop_body, label %exit

loop_body:
%4 = load i32, i32* %1, align 4   ;-- load i
%5 = and i32 %4, 1                ;-- i & 1
%6 = icmp eq i32 %5, 0            ;-- (i & 1) == 0
br i1 %6, label %even_branch, label %odd_branch

even_branch:
%7 = load i32, i32* %1, align 4   ;-- load i
%8 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([12 x i8], [12 x i8]* @"EVEN_STR", i32 0, i32 0), i32 %7)
br label %loop_increment

odd_branch:
%9 = load i32, i32* %1, align 4   ;-- load i
%10 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @"ODD_STR", i32 0, i32 0), i32 %9)
br label %loop_increment

loop_increment:
%11 = load i32, i32* %1, align 4  ;-- load i
%12 = add i32 %11, 1              ;-- increment i
store i32 %12, i32* %1, align 4   ;-- store i
br label %loop

exit:
ret i32 0
}

attributes #0 = { noinline nounwind optnone uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
```
Output:
```0 is even
1 is odd
2 is even
3 is odd```

## Logo

```to even? :num
output equal? 0 modulo :num 2
end```

## Logtalk

```:- object(even_odd).

:- public(test_mod/1).
test_mod(I) :-
(   I mod 2 =:= 0 ->
write(even), nl
;   write(odd), nl
).

:- public(test_bit/1).
test_bit(I) :-
(   I /\ 1 =:= 1 ->
write(odd), nl
;   write(even), nl
).

:- end_object.
```
Output:
```| ?- even_odd::test_mod(1).
odd
yes

| ?- even_odd::test_mod(2).
even
yes

| ?- even_odd::test_bit(1).
odd
yes

| ?- even_odd::test_bit(2).
even
yes
```

## LOLCODE

```HAI 1.4
I HAS A integer
GIMMEH integer
I HAS A remainder
remainder R MOD OF integer AN 2
BOTH SAEM remainder AN 1, O RLY?
YA RLY
VISIBLE "The integer is odd."
NO WAI
VISIBLE "The integer is even."
OIC
KTHXBYE```

## Lua

```-- test for even number
if n % 2 == 0 then
print "The number is even"
end

-- test for odd number
if not (n % 2 == 0) then
print "The number is odd"
end
```

## M2000 Interpreter

Binary.Add take any numeric type, but value must be in range of 0 to 0xFFFFFFFF So Mod if a perfect choice, using it with Decimals (character @ indicate a Decimal type or literal). Variable a take the type of input. There is no reason here to write it as def Odd(a as decimal)= binary.and(Abs(a), 1)=1

Def used to define variables (an error occur if same variable exist), or to define one line local functions. If a function exist then replace code. This is the same for modules/functions, a newer definition alter an old definition with same name, in current module if they are local, or global if they defined as global, like this Function Global F(x) { code block here}.

A function F(x) {} is same as

```Function F {
code here
}
```

The same hold for Def Odd(a)=binary.and(Abs(a), 1)=1 Interpreter execute this:

```Function Odd {
=binary.and(Abs(a), 1)=1
}
```

So here is the task. Show an overflow from a decimal, then change function.

```Module CheckOdd {
Def Odd(a)= binary.and(Abs(a), 1)=1
Print Odd(-5), Odd(6), Odd(11)
Try {
Print Odd(21212121212122122122121@)
}
Print Error\$    ' overflow

def Odd(a)= Int(Abs(a)) mod 2 =1
Print Odd(21212121212122122122121@)
Print Odd(-5), Odd(6), Odd(11)
}
CheckOdd```

## M4

```define(`even', `ifelse(eval(`\$1'%2),0,True,False)')
define(`odd',  `ifelse(eval(`\$1'%2),0,False,True)')

even(13)
even(8)

odd(5)
odd(0)```

## Maple

```EvenOrOdd := proc( x::integer )
if x mod 2 = 0 then
print("Even"):
else
print("Odd"):
end if:
end proc:
EvenOrOdd(9);```
`"Odd"`

## Mathematica / Wolfram Language

```EvenQ
```

## MATLAB / Octave

Bitwise And:

```   isOdd  =  logical(bitand(N,1));
isEven = ~logical(bitand(N,1));
```

Remainder of division by two

```   isOdd  =  logical(rem(N,2));
isEven = ~logical(rem(N,2));
```

Modulo: 2

```   isOdd  =  logical(mod(N,2));
isEven = ~logical(mod(N,2));
```

## Maxima

```evenp(n);
oddp(n);
```

## MAXScript

```-- MAXScript : Even or Odd : N.H. 2019
-- Open the MAXScript Listener for input and output
userInt = getKBValue prompt:"Enter an integer and i will tell you if its Even or Odd : "
if classOf userInt != Integer then print "The value you enter must be an integer"
else if (Mod userInt 2) == 0 Then Print "Your number is even"
else Print "Your number is odd"```

## Mercury

Mercury's 'int' module provides tests for even/odd, along with all the operators that would be otherwise used to implement them.

```even(N)  % in a body, suceeeds iff N is even.
odd(N).  % in a body, succeeds iff N is odd.

% rolling our own:
:- pred even(int::in) is semidet.

% It's an error to have all three in one module, mind; even/1 would fail to check as semidet.
even(N) :- N mod 2 = 0.   % using division that truncates towards -infinity
even(N) :- N rem 2 = 0.   % using division that truncates towards zero
even(N) :- N /\ 1 = 0.    % using bit-wise and.```

## min

Works with: min version 0.19.3
```3 even?
4 even?
5 odd?
get-stack print```
Output:
```(false true true)
```

## MiniScript

```for i in range(-4, 4)
if i % 2 == 0 then print i + " is even" else print i + " is odd"
end for
```
Output:
```-4 is even
-3 is odd
-2 is even
-1 is odd
0 is even
1 is odd
2 is even
3 is odd
4 is even```

## MIPS Assembly

This uses bitwise AND

```.data
even_str: .asciiz "Even"
odd_str: .asciiz "Odd"

.text
#set syscall to get integer from user
li \$v0,5
syscall

#perform bitwise AND and store in \$a0
and \$a0,\$v0,1

#set syscall to print dytomh
li \$v0,4

#jump to odd if the result of the AND operation
beq \$a0,1,odd
even:
#load even_str message, and print
la \$a0,even_str
syscall

#exit program
li \$v0,10
syscall

odd:
#load odd_str message, and print
la \$a0,odd_str
syscall

#exit program
li \$v0,10
syscall```

## МК-61/52

```/	2	{x}	ЗН
```

Result: "0" - number is even; "1" - number is odd.

## ML

```fun even( x: int ) = (x mod 2 = 0);
fun odd( x: int ) = (x mod 2 = 1);```

### mLite

```fun odd
(x rem 2 = 1) = true
| 	_ 	      = false
;

fun even
(x rem 2 = 0) = true
| 	_ 	      = false
;
```

## Modula-2

```MODULE EvenOrOdd;
FROM FormatString IMPORT FormatString;
FROM Terminal IMPORT WriteString,ReadChar;

VAR
buf : ARRAY[0..63] OF CHAR;
i : INTEGER;
BEGIN
FOR i:=-5 TO 5 DO
FormatString("%i is even: %b\n", buf, i, i MOD 2 = 0);
WriteString(buf)
END;

END EvenOrOdd.
```

## Nanoquery

```def isEven(n)
if ((n % 2) = 1)
return false
else
return true
end
end

for i in range(1, 10)
print i
if isEven(i)
println " is even."
else
println " is odd."
end
end```
Output:
```1 is odd.
2 is even.
3 is odd.
4 is even.
5 is odd.
6 is even.
7 is odd.
8 is even.
9 is odd.
10 is even.```

## Neko

```var number = 6;

if(number % 2 == 0) {
\$print("Even");
} else {
\$print("Odd");
}```
Output:
`Even`

## NESL

NESL provides evenp and oddp functions, but they wouldn't be hard to reimplement.

```function even(n) = mod(n, 2) == 0;

% test the function by applying it to the first ten positive integers: %
{even(n) : n in [1:11]};```
Output:
`it = [F, T, F, T, F, T, F, T, F, T] : [bool]`

## NetRexx

```/* NetRexx */
options replace format comments java crossref symbols nobinary

say 'Val'.right(5)': mod  - ver  - pos  - bits'
say '---'.right(5)': ---- + ---- + ---- + ----'
loop nn = -15 to 15 by 3
say nn.right(5)':' eo(isEven(nn)) '-' eo(isEven(nn, 'v')) '-' eo(isEven(nn, 'p')) '-' eo(isEven(nn, 'b'))
end nn
return

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- Overloaded method.  Default is to use the remainder specialization below
method isEven(anInt, meth = 'R') public static returns boolean
select case meth.upper().left(1)
when 'R' then eo = isEvenRemainder(anInt)
when 'V' then eo = isEvenVerify(anInt)
when 'P' then eo = isEvenPos(anInt)
when 'B' then eo = isEvenBits(anInt)
otherwise     eo = isEvenRemainder(anInt) -- default
end
return eo

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method isEvenRemainder(anInt) public static returns boolean
return anInt // 2 == 0

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method isEvenVerify(anInt) public static returns boolean
return anInt.right(1).verify('02468') == 0

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method isEvenPos(anInt) public static returns boolean
return '13579'.pos(anInt.right(1)) == 0

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method isEvenBits(anInt) public static returns boolean
return \(anInt.d2x(1).x2b().right(1))

-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
method eo(state = boolean) public static
if state then sv = 'Even'
else sv = 'Odd'
return sv.left(4)
```
Output:
```  Val: mod  - ver  - pos  - bits
---: ---- + ---- + ---- + ----
-15: Odd  - Odd  - Odd  - Odd
-12: Even - Even - Even - Even
-9: Odd  - Odd  - Odd  - Odd
-6: Even - Even - Even - Even
-3: Odd  - Odd  - Odd  - Odd
0: Even - Even - Even - Even
3: Odd  - Odd  - Odd  - Odd
6: Even - Even - Even - Even
9: Odd  - Odd  - Odd  - Odd
12: Even - Even - Even - Even
15: Odd  - Odd  - Odd  - Odd
```

## Never

```func isOdd(n : int) -> int {
n % 2 == 1
}

func isEven(n : int) -> int {
n % 2 == 0
}```

## NewLISP

```(odd? 1)
(even? 2)
```

## Nim

```# Least signficant bit:
proc isOdd(i: int): bool = (i and 1) != 0
proc isEven(i: int): bool = (i and 1) == 0

# Modulo:
proc isOdd2(i: int): bool = (i mod 2) != 0
proc isEven2(i: int): bool = (i mod 2) == 0

# Bit Shifting:
proc isOdd3(n: int): bool = n != ((n shr 1) shl 1)
proc isEven3(n: int): bool = n == ((n shr 1) shl 1)

echo isEven(1)
echo isOdd2(5)
```

## Oberon-2

Works with: oo2c
```MODULE EvenOrOdd;
IMPORT
S := SYSTEM,
Out;
VAR
x: INTEGER;
s: SET;

BEGIN
x := 10;Out.Int(x,0);
IF ODD(x) THEN Out.String(" odd") ELSE Out.String(" even") END;
Out.Ln;

x := 11;s := S.VAL(SET,LONG(x));Out.Int(x,0);
IF 0 IN s THEN Out.String(" odd") ELSE Out.String(" even") END;
Out.Ln;

x := 12;Out.Int(x,0);
IF x MOD 2 # 0 THEN Out.String(" odd") ELSE Out.String(" even") END;
Out.Ln
END EvenOrOdd.
```
Output:
```10 even
11 odd
12 even
```

## Objeck

```a := Console->ReadString()->ToInt();
if(a % 2 = 0) {
"even"->PrintLine();
}
else {
"odd"->PrintLine();
};```

## OCaml

Modulo:

```let is_even d =
(d mod 2) = 0

let is_odd d =
(d mod 2) <> 0
```

Bitwise and:

```let is_even d =
(d land 1) = 0

let is_odd d =
(d land 1) <> 0
```

An instructive view on functional programming and recursion:

```(* hmm, only valid for N >= 0 *)
let rec myeven = function
| 0 -> true
| 1 -> false
| n -> myeven (n - 2)

(* and here we have the not function in if form *)
let myodd n = if myeven n then false else true
```

## Oforth

```12 isEven
12 isOdd```

## Ol

Actually, 'even?' and 'odd?' functions are built-in. But,

```; 1. Check the least significant bit.
(define (even? i)
(if (eq? (band i 1) 0) #t #f))
(define (odd? i)
(if (eq? (band i 1) 1) #t #f))

(print (if (even? 12345678987654321) "even" "odd")) ; ==> odd
(print (if (odd? 12345678987654321) "odd" "even"))  ; ==> odd
(print (if (even? 1234567898765432) "even" "odd"))  ; ==> even
(print (if (odd? 1234567898765432) "odd" "even"))   ; ==> even

; 2. Divide i by 2. The remainder equals 0 iff i is even.
(define (even? i)
(if (eq? (remainder i 2) 0) #t #f))
(define (odd? i)
(if (eq? (remainder i 2) 1) #t #f))

(print (if (even? 12345678987654321) "even" "odd")) ; ==> odd
(print (if (odd? 12345678987654321) "odd" "even"))  ; ==> odd
(print (if (even? 1234567898765432) "even" "odd"))  ; ==> even
(print (if (odd? 1234567898765432) "odd" "even"))   ; ==> even

; 3. Use modular congruences. Same as 2.
(define (even? i)
(if (eq? (mod i 2) 0) #t #f))
(define (odd? i)
(if (eq? (mod i 2) 1) #t #f))

(print (if (even? 12345678987654321) "even" "odd")) ; ==> odd
(print (if (odd? 12345678987654321) "odd" "even"))  ; ==> odd
(print (if (even? 1234567898765432) "even" "odd"))  ; ==> even
(print (if (odd? 1234567898765432) "odd" "even"))   ; ==> even
```

## OOC

```// Using the modulo operator
even: func (n: Int) -> Bool {
(n % 2) == 0
}

// Using bitwise and
odd: func (n: Int) -> Bool {
(n & 1) == 1
}
```

## PARI/GP

GP does not have a built-in predicate for testing parity, but it's easy to code:

`odd(n)=n%2;`

Alternately:

`odd(n)=bitand(n,1);`

PARI can use the same method as C for testing individual words. For multiprecision integers (t_INT), use `mpodd`. If the number is known to be nonzero, `mod2` is (insignificantly) faster.

## Pascal

Built-in boolean function odd:

```isOdd := odd(someIntegerNumber);
```

bitwise and:

```function isOdd(Number: integer): boolean
begin
isOdd := boolean(Number and 1)
end;
```

Dividing and multiplying by 2 and test on equality:

```function isEven(Number: integer): boolean
begin
isEven := (Number = ((Number div 2) * 2))
end;
```

Using built-in modulo

```function isOdd(Number: integer): boolean
begin
isOdd := boolean(Number mod 2)
end;
```

## Perl

```for(0..10){
print "\$_ is ", qw(even odd)[\$_ % 2],"\n";
}
```

or

```print 6 % 2  ? 'odd' : 'even';   # prints even
```

## Phix

There are builtin routines odd() and even() which return true/false - note however they will round non-integer arguments to the nearest whole number, which might be confusing. The mpz_odd() and mpz_even() are similar, but without any way to pass them fractions. In fact odd() invokes and_bits(i,1)=1 and even() invokes and_bits(i,1)=0, so no difference there, and "i&&1" is just shorthand for and_bits(i,1). Lastly remainder(i,2) can also validly be used, however "true" for odd numbers is actually 1 for positive odd integers and -1 for negative odd integers, plus fractions are preserved, so "remainder(i,2)==0" is perhaps for some uses a more flexible and accurate "even"/"not even" test.

```with javascript_semantics
include mpfr.e
mpz z = mpz_init()
printf(1," i    odd  even  &&1  rmdr(2)\n")
for i=-5 to 5 do
mpz_set_si(z,i)
printf(1,"%2d: %5t %5t %3d %5d\n",{i,odd(i),even(i),i&&1,remainder(i,2)})
end for
```
Output:
``` i    odd  even  &&1  rmdr(2)
-5:  true false   1    -1
-4: false  true   0     0
-3:  true false   1    -1
-2: false  true   0     0
-1:  true false   1    -1
0: false  true   0     0
1:  true false   1     1
2: false  true   0     0
3:  true false   1     1
4: false  true   0     0
5:  true false   1     1
```

## Phixmonti

```-5 5 2 tolist for
dup print " " print 2 mod if "Odd" else "Even" endif print nl
endfor```

## PHP

```// using bitwise and to check least significant digit
echo (2 & 1) ? 'odd' : 'even';
echo (3 & 1) ? 'odd' : 'even';

// using modulo
echo (3 % 2) ? 'odd' : 'even';
echo (4 % 2) ? 'odd' : 'even';
```
Output:
```even
odd
odd
even```

## Picat

Works with: Picat
```% Bitwise and
is_even_bitwise(I) = cond(I /\ 1 == 0, true, false).

% Modulo
is_even_mod(I) = cond(I mod 2 == 0, true, false).

% Remainder
is_even_rem(I) = cond(I rem 2 == 0, true, false).

yes_or_no(B) = YN =>
B = true, YN = "Yes";
B = false, YN = "No".

main :-
foreach (I in 2..3)
printf("%d is even? %s\n", I, yes_or_no(is_even_bitwise(I))),
printf("%d is even? %s\n", I, yes_or_no(is_even_mod(I))),
printf("%d is even? %s\n", I, yes_or_no(is_even_rem(I)))
end.```
Output:
```2 is even? Yes
2 is even? Yes
2 is even? Yes
3 is even? No
3 is even? No
3 is even? No
```

Note: Picat has even/1 and odd/1 as built-ins predicates.

## PicoLisp

PicoLisp doesn't have a built-in predicate for that. Using 'bit?' is the easiest and most efficient. The bit test with 1 will return NIL if the number is even.

```: (bit? 1 3)
-> 1  # Odd

: (bit? 1 4)
-> NIL  # Even```

## Pike

```> int i = 73;
> (i&1);
Result: 1
> i%2;
Result: 1
```

## PL/I

`i = iand(i,1)`

The result is 1 when i is odd, and 0 when i is even.

## PL/M

In PL/M, even numbers are falsy and odd numbers are truthy, so no explicit test is needed at all.

```100H:
BDOS: PROCEDURE (FN, ARG); DECLARE FN BYTE, ARG ADDRESS; GO TO 5; END BDOS;
EXIT: PROCEDURE; CALL BDOS(0,0); END EXIT;
PUT\$CHAR: PROCEDURE (CH); DECLARE CH BYTE; CALL BDOS(2, CH); END PUT\$CHAR;
PRINT: PROCEDURE (S); DECLARE S ADDRESS; CALL BDOS(9, S); END PRINT;

DECLARE I BYTE;
DO I='0' TO '9';
CALL PUT\$CHAR(I);
CALL PRINT(.' IS \$');
IF I THEN
CALL PRINT(.'ODD\$');
ELSE
CALL PRINT(.'EVEN\$');
CALL PRINT(.(13,10,'\$'));
END;

CALL EXIT;
EOF```
Output:
```0 IS EVEN
1 IS ODD
2 IS EVEN
3 IS ODD
4 IS EVEN
5 IS ODD
6 IS EVEN
7 IS ODD
8 IS EVEN
9 IS ODD```

## Plain English

The noodle comes with even and odd deciders.

```To run:
Start up.
If 56 is even, write "56 is even!" to the console.
If 4 is odd, write "4 is odd!" to the console.
Wait for the escape key.
Shut down.```
Output:
```56 is even!
```

## PowerShell

Works with: PowerShell version 2

### Predicate

A predicate can be used with BigInteger objects. Even/odd predicates to not exist for basic value types. Type accelerator [bigint] can be used in place of [System.Numerics.BigInteger].

```\$IsOdd  = -not ( [bigint]\$N ).IsEven
\$IsEven =      ( [bigint]\$N ).IsEven
```

### Least significant digit

```\$IsOdd  = [boolean]( \$N -band 1 )
\$IsEven = [boolean]( \$N -band 0 )
```

### Remainder

Despite being known as a modulus operator, the % operator in PowerShell actually returns a remainder. As such, when testing negative numbers it returns the true modulus result minus M. In this specific case, it returns -1 for odd negative numbers. Thus we test for not zero for odd numbers.

```\$IsOdd  = \$N % 2 -ne 0
\$IsEven = \$N % 2 -eq 0
```

## Processing

```boolean isEven(int i){
return i%2 == 0;
}

boolean isOdd(int i){
return i%2 == 1;
}```

## Prolog

Prolog does not provide special even or odd predicates as one can simply write "0 is N mod 2" to test whether the integer N is even. To illustrate, here is a predicate that can be used both to test whether an integer is even and to generate the non-negative even numbers:

```  even(N) :-
(between(0, inf, N); integer(N) ),
0 is N mod 2.
```

### Least Significant Bit

If N is a positive integer, then lsb(N) is the offset of its least significant bit, so we could write:

```  odd(N) :- N = 0 -> false; 0 is lsb(abs(N)).
```

## PureBasic

```;use last bit method
isOdd = i & 1         ;isOdd is non-zero if i is odd
isEven = i & 1 ! 1    ;isEven is non-zero if i is even

;use modular method
isOdd = i % 2         ;isOdd is non-zero if i is odd
isEven = i % 2 ! 1    ;isEven is non-zero if i is even
```

## Python

### Python: Using the least-significant bit method

```>>> def is_odd(i): return bool(i & 1)

>>> def is_even(i): return not is_odd(i)

>>> [(j, is_odd(j)) for j in range(10)]
[(0, False), (1, True), (2, False), (3, True), (4, False), (5, True), (6, False), (7, True), (8, False), (9, True)]
>>> [(j, is_even(j)) for j in range(10)]
[(0, True), (1, False), (2, True), (3, False), (4, True), (5, False), (6, True), (7, False), (8, True), (9, False)]
>>>
```

### Python: Using modular congruences

```>> def is_even(i):
return (i % 2) == 0

>>> is_even(1)
False
>>> is_even(2)
True
>>>
```

## Quackery

```[ 1 & ]     is odd  ( n --> b )

[ odd not ] is even ( n --> b )```
Output:

In the Quackery shell (REPL):

```/O> 10 even
... 10 odd
... 11 even
... 11 odd
...

Stack: 1 0 0 1
```

### Quackery: With Anonymous Mutual Recursion

Adapted from the example code at wp:Mutual recursion#Basic examples, with the additional observation that the parity of a negative number is the same as the parity of its absolute value.

```  [ abs

' [ dup 0 = iff
[ 2drop true ] done
1 - this swap rot do ] ( x n --> b )

' [ dup 0 = iff
[ 2drop false ] done
1 - this swap rot do ] ( x n --> b )

unrot do ]                 is even ( n --> b )

11 times
[ i^ 5 - dup echo
say " is "
even iff [ \$ "even" ]
else [ \$ "odd" ]
echo\$ say "." cr ]```
Output:
```-5 is odd.
-4 is even.
-3 is odd.
-2 is even.
-1 is odd.
0 is even.
1 is odd.
2 is even.
3 is odd.
4 is even.
5 is odd.```

## R

```is.even <- function(x) !is.odd(x)

is.odd <- function(x) intToBits(x) == 1
#or
is.odd <- function(x) x %% 2 == 1
```

## Racket

With built in predicates:

```(even? 6) ; -> true
(even? 5) ; -> false
(odd? 6) ; -> false
(odd? 5) ; -> true
```

With modular arithmetic:

```(define (my-even? x)
(= (modulo x 2) 0))

(define (my-odd? x)
(= (modulo x 2) 1))
```

## Raku

(formerly Perl 6) Raku doesn't have a built-in for this, but with subsets it's easy to define a predicate for it.

```subset Even of Int where * %% 2;
subset Odd of Int where * % 2;

say 1 ~~ Even; # false
say 1 ~~ Odd;  # true
say 1.5 ~~ Odd # false ( 1.5 is not an Int )
```

## Rascal

```public bool isEven(int n) = (n % 2) == 0;
public bool isOdd(int n) = (n % 2) == 1;```

Or with block quotes:

```public bool isEven(int n){return (n % 2) == 0;}
public bool isOdd(int n){return (n % 2) == 1;}```

## Rapira

```fun is_even(n)
return (n /% 2) = 0
end```

## Red

```Red [
date: 2021-10-24
red-version: 0.6.4
description: "Test whether an integer is even or odd."
]

print even? 10 ;== true
print odd? 10 ;== false
```

## ReScript

```let is_even = d => mod(d, 2) == 0

let is_odd = d => mod(d, 2) != 0```

## REXX

Programming note:   division by   1   (one)   in REXX is a way to normalize a number:

• by removing a superfluous leading   +   sign
• by removing superfluous leading zeroes
• by removing superfluous trailing zeroes
• by removing a trailing decimal point
• possible converting an exponentiated number
• possible rounding the number to the current digits

Programming note:   the last method is the fastest method in REXX to determine oddness/evenness.
It requires a sparse stemmed array     !.     be defined in the program's prologue (or elsewhere).
This method gets its speed from   not   using any BIF and   not   performing any (remainder) division.

Some notes on programming styles:   If (execution) speed isn't an issue, then the 1st test method
shown would be the simplest   (in terms of coding the concisest/tightest/smallest code).   The other test
methods differ mostly in programming techniques, mostly depending on the REXX programmer's style.
The last method shown is the fastest algorithm, albeit it might be a bit obtuse (without comments) to a
novice reader of the REXX language   (and it requires additional REXX statement baggage).

```/*REXX program tests and displays if an integer is  even or odd  using different styles.*/
!.=0;   do j=0  by 2  to 8;   !.j=1;   end       /*assign  0,2,4,6,8  to a "true" value.*/
/* [↑]  assigns even digits to  "true".*/
numeric digits 1000                              /*handle most huge numbers from the CL.*/
parse arg x _ .                                  /*get an argument from the command line*/
if x==''               then call terr "no integer input (argument)."
if _\=='' | arg()\==1  then call terr "too many arguments: "          _  arg(2)
if \datatype(x, 'N')   then call terr "argument isn't numeric: "      x
if \datatype(x, 'W')   then call terr "argument isn't an integer: "   x
y=abs(x)/1                                       /*in case  X  is negative or malformed,*/
/* [↑]  remainder of neg # might be -1.*/
/*malformed #s: 007  9.0  4.8e1  .21e2 */
call tell 'remainder method (oddness)'
if y//2  then say  x  'is odd'
else say  x  'is even'
/* [↑]  uses division to get remainder.*/

call tell 'rightmost digit using BIF (not evenness)'
_=right(y, 1)
if pos(_, 86420)==0  then say x 'is odd'
else say x 'is even'
/* [↑]  uses 2 BIF (built─in functions)*/

call tell 'rightmost digit using BIF (evenness)'
_=right(y, 1)
if pos(_, 86420)\==0  then say x 'is even'
else say x 'is odd'
/* [↑]  uses 2 BIF (built─in functions)*/

call tell 'even rightmost digit using array (evenness)'
_=right(y, 1)
if !._  then say x 'is even'
else say x 'is odd'
/* [↑]  uses a BIF (built─in function).*/

call tell 'remainder of division via function invoke (evenness)'
if even(y)  then say x 'is even'
else say x 'is odd'
/* [↑]  uses (even) function invocation*/

call tell 'remainder of division via function invoke (oddness)'
if odd(y)  then say x 'is odd'
else say x 'is even'
/* [↑]  uses (odd)  function invocation*/

call tell 'rightmost digit using BIF (not oddness)'
_=right(y, 1)
if pos(_, 13579)==0  then say x 'is even'
else say x 'is odd'
/* [↑]  uses 2 BIF (built─in functions)*/

call tell 'rightmost (binary) bit (oddness)'
if right(x2b(d2x(y)), 1)  then say x 'is odd'
else say x 'is even'
/* [↑]  requires extra numeric digits. */

call tell 'parse statement using BIF (not oddness)'
parse var  y   ''  -1  _                         /*obtain last decimal digit of the Y #.*/
if pos(_, 02468)==0  then say x 'is odd'
else say x 'is even'
/* [↑]  uses a BIF (built─in function).*/

call tell 'parse statement using array (evenness)'
parse var  y   ''  -1  _                         /*obtain last decimal digit of the Y #.*/
if !._  then say  x  'is even'
else say  x  'is odd'
/* [↑]  this is the fastest algorithm. */
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
even:                     return \( arg(1)//2 )  /*returns "evenness" of arg, version 1.*/
even:                     return    arg(1)//2==0 /*   "         "      "  "      "    2.*/
even: parse arg '' -1 _;  return !._             /*   "         "      "  "      "    3.*/
/*last version shown is the fastest.   */
odd:                      return   arg(1)//2     /*returns  "oddness" of the argument.  */
tell: say;   say center('using the' arg(1), 79, "═");                    return
terr: say;   say '***error***';     say;    say arg(1);    say;          exit 13
```

output   when using the input of:   0

```═════════════════════using the remainder method (oddness)══════════════════════
0 is even

══════════════using the rightmost digit using BIF (not evenness)═══════════════
0 is even

════════════════using the rightmost digit using BIF (evenness)═════════════════
0 is even

═════════════using the even rightmost digit using array (evenness)═════════════
0 is even

════════using the remainder of division via function invoke (evenness)═════════
0 is even

═════════using the remainder of division via function invoke (oddness)═════════
0 is even

═══════════════using the rightmost digit using BIF (not oddness)═══════════════
0 is even

══════════════════using the rightmost (binary) bit (oddness)═══════════════════
0 is even

═══════════════using the parse statement using BIF (not oddness)═══════════════
0 is even

═══════════════using the parse statement using array (evenness)════════════════
0 is even
```

output   when using the input of:   9876543210987654321098765432109876543210987654321

```═════════════════════using the remainder method (oddness)══════════════════════
9876543210987654321098765432109876543210987654321 is odd

(rest of the output was elided.)
```

output   when using the input of:   .6821e4

```═════════════════════using the remainder method (oddness)══════════════════════
.8621e4 is odd

(rest of the output was elided.)
```

output   when using the input of:   -9411

```═════════════════════using the remainder method (oddness)══════════════════════
-9411 is odd

(rest of the output was elided.)
```

## Ring

```size = 10
for i = 1 to size
if i % 2 = 1 see "" + i + " is odd" + nl
else see "" + i + " is even" + nl ok
next```

## Ruby

In Ruby, integers behave like objects, so they respond to methods like : 5.even? resulting to false

```print "evens: "
p -5.upto(5).select(&:even?)
print "odds: "
p -5.upto(5).select(&:odd?)
```
Output:
```evens: [-4, -2, 0, 2, 4]
odds: [-5, -3, -1, 1, 3, 5]```

Other ways to test even-ness:

```n & 1 == 0
quotient, remainder = n.divmod(2); remainder == 0

# The next way only works when n.to_f/2 is exact.
# If Float is IEEE double, then -2**53 .. 2**53 must include n.
n.to_f/2 == n/2

# You can use the bracket operator to access the i'th bit
# of a Fixnum or Bignum (i = 0 means least significant bit)
n.zero?
```

## Run BASIC

Works with: QBasic
```for i = 1 to 10
if i and 1 then print i;" is odd" else print i;" is even"
next i```
```1 is odd
2 is even
3 is odd
4 is even
5 is odd
6 is even
7 is odd
8 is even
9 is odd
10 is even
```

## Rust

Checking the least significant digit:

```let is_odd = |x: i32| x & 1 == 1;
let is_even = |x: i32| x & 1 == 0;
```

Using modular congruences:

```let is_odd = |x: i32| x % 2 != 0;
let is_even = |x: i32| x % 2 == 0;
```

## S-BASIC

S-BASIC lacks a MOD operator but supports bitwise operations on integer variables, so that is the approach taken.

```rem - return true (-1) if even, otherwise false (0)
function even(i = integer) = integer
var one = integer    rem - both operands must be variables
one = 1
end = ((i and one) = 0)

rem - exercise the function
var i = integer
for i = 1 to 10 step 3
print i; " is ";
if even(i) then
print "even"
else
print "odd"
next

end
```
Output:
``` 1 is odd
4 is even
7 is odd
10 is even```

## Scala

```def isEven( v:Int ) : Boolean = v % 2 == 0
def isOdd( v:Int ) : Boolean = v % 2 != 0
```

Accept any numeric type as an argument:

```def isEven( v:Number ) : Boolean = v.longValue % 2 == 0
def isOdd( v:Number ) : Boolean = v.longValue % 2 != 0
```
Output:
```isOdd( 81 )                     // Results in true
isEven( BigInt(378) )           // Results in true
isEven( 234.05003513013145 )    // Results in true```

## Scheme

`even?` and `odd?` functions are built-in (R4RS, R5RS, and R6RS):

```> (even? 5)
#f
> (even? 42)
#t
> (odd? 5)
#t
> (odd? 42)
#f
```

## Seed7

Test whether an integer or bigInteger is odd:

`odd(aNumber)`

Test whether an integer or bigInteger is even:

`not odd(aNumber)`

## SenseTalk

```set num to random of 100 -- start with a random number from 1 to 100

// use the 'is a' operator to test the value
if num is an odd number then put num & " is odd"

// see if num is divisible by 2
if num is divisible by 2 then put num & " is even (is divisible by 2)"

// check to see if the remainder is 0 when dividing by 2
if num rem 2 is 0 then put num & " is even (zero remainder)"```

## SequenceL

```even(x) := x mod 2 = 0;
odd(x) := x mod 2 = 1;```
Output:
```cmd:>even(1 ... 10)
[false,true,false,true,false,true,false,true,false,true]
cmd:>odd(1 ... 10)
[true,false,true,false,true,false,true,false,true,false]
```

## SETL

SETL provides built-in even and odd functions. This short program illustrates their use.

```xs := {1..10};
evens := {x in xs | even( x )};
odds := {x in xs | odd( x )};
print( evens );
print( odds );```
Output:
```{2 4 6 8 10}
{1 3 5 7 9}```

## Shen

Mutual Recursion:

```(define even?
0 -> true
X -> (odd? (- X 1)))

(define odd?
0 -> false
X -> (even? (- X 1)))
```

Modulo:

```(define even? X -> (= 0 (shen.mod X 2)))

(define odd? X -> (not (= 0 (shen.mod X 2))))
```

## Sidef

Built-in methods:

```var n = 42;
say n.is_odd;       # false
say n.is_even;      # true
```

Checking the last significant digit:

```func is_odd(n)  { n&1 == 1 };
func is_even(n) { n&1 == 0 };
```

Using modular congruences:

```func is_odd(n)  { n%2 == 1 };
func is_even(n) { n%2 == 0 };
```

## Smalltalk

Using the built in methods on Number class:

```5 even
5 odd
```

even is implemented as follows:

```Number>>even
^((self digitAt: 1) bitAnd: 1) = 0
```

## SNOBOL4

Works with: Macro SNOBOL4 in C
Works with: Spitbol
Works with: SNOBOL4+
```      DEFINE('even(n)')                         :(even_end)
even  even = (EQ(REMDR(n, 2), 0) 'even', 'odd') :(RETURN)
even_end

OUTPUT = "-2 is " even(-2)
OUTPUT = "-1 is " even(-1)
OUTPUT = "0 is " even(0)
OUTPUT = "1 is " even(1)
OUTPUT = "2 is " even(2)
END```
Output:
```-2 is even
-1 is odd
0 is even
1 is odd
2 is even

```

## SNUSP

```\$====!/?\==even#
- -
#odd==\?/```

## SPL

```> n, 0..9
? #.even(n), #.output(n," even")
? #.odd(n), #.output(n," odd")
<```
Output:
```0 even
1 odd
2 even
3 odd
4 even
5 odd
6 even
7 odd
8 even
9 odd
```

## SQL

Database vendors can't agree on how to get a remainder. This should work for many, including Oracle. For others, including MS SQL Server, try "int % 2" instead of "mod(int, 2)".

```-- Setup a table with some integers
create table ints(int integer);
insert into ints values (-1);
insert into ints values (0);
insert into ints values (1);
insert into ints values (2);

-- Are they even or odd?
select
int,
case mod(int, 2) when 0 then 'Even' else 'Odd' end
from
ints;
```
Output:
```       INT CASE
---------- ----
-1 Odd
0 Even
1 Odd
2 Even```

## SSEM

The SSEM doesn't provide AND, but for once the instruction set does allow the problem to be solved quite elegantly (albeit extravagantly slowly). Load the value of $n$ into storage address 15. The first three instructions test whether $n$ is positive, and replace it with its negation if it isn't. We then loop, subtracting 2 each time and testing whether we have got down either to 0 or to 1. When we have, the computer will halt with the accumulator storing 0 if $n$ was even or 1 if it was odd.

Note that the constant 2, stored at address 14, does double service: it is the operand for the Sub. instruction at address 6 and also the jump target returning to the top of the main loop (which is at address 2 + 1 = 3).

For larger positive or smaller negative values of $n$ , you should be ready with something else to do while the machine is working: a test run took several minutes to confirm that 32,769 was odd.

```11110000000000100000000000000000   0. -15 to c
00000000000000110000000000000000   1. Test
11110000000001100000000000000000   2. c to 15
11110000000000100000000000000000   3. -15 to c
00001000000001100000000000000000   4. c to 16
00001000000000100000000000000000   5. -16 to c
01110000000000010000000000000000   6. Sub. 14
11110000000001100000000000000000   7. c to 15
10110000000000010000000000000000   8. Sub. 13
00000000000000110000000000000000   9. Test
01110000000000000000000000000000  10. 14 to CI
11110000000000100000000000000000  11. -15 to c
00000000000001110000000000000000  12. Stop
10000000000000000000000000000000  13. 1
01000000000000000000000000000000  14. 2```

## Standard ML

```fun even n =
n mod 2 = 0;

fun odd n =
n mod 2 <> 0;

(* bitwise and *)

type werd = Word.word;

fun evenbitw(w: werd) =
Word.andb(w, 0w2) = 0w0;

fun oddbitw(w: werd) =
Word.andb(w, 0w2) <> 0w0;
```

## Stata

```mata
function iseven(n) {
return(mod(n,2)==0)
}

function isodd(n) {
return(mod(n,2)==1)
}
end
```

## Swift

```func isEven(n:Int) -> Bool {

// Bitwise check
if (n & 1 != 0) {
return false
}

// Mod check
if (n % 2 != 0) {
return false
}
return true
}
```

## Symsyn

```n : 23

if n bit 0
'n is odd' []
else
'n is even' []```

## Tcl

```package require Tcl 8.5

# Bitwise test is the most efficient
proc tcl::mathfunc::isOdd x  { expr {\$x & 1} }
proc tcl::mathfunc::isEven x { expr {!(\$x & 1)} }

puts " # O E"
puts 24:[expr isOdd(24)],[expr isEven(24)]
puts 49:[expr isOdd(49)],[expr isEven(49)]
```
Output:
``` # O E
24:0,1
49:1,0
```

## TI-83 BASIC

TI-83 BASIC does not have a modulus operator.

```If fPart(.5Ans
Then
Disp "ODD
Else
Disp "EVEN
End```

## TUSCRIPT

```\$\$ MODE TUSCRIPT
LOOP n=-5,5
x=MOD(n,2)
SELECT x
CASE 0
PRINT n," is even"
DEFAULT
PRINT n," is odd"
ENDSELECT
ENDLOOP```
Output:
```-5 is odd
-4 is even
-3 is odd
-2 is even
-1 is odd
0 is even
1 is odd
2 is even
3 is odd
4 is even
5 is odd
```

## UNIX Shell

```iseven() {
[[ \$((\$1%2)) -eq 0 ]] && return 0
return 1
}
```

## Ursa

```decl int input
set input (in int console)
if (= (mod input 2) 1)
out "odd" endl console
else
out "even" endl console
end if```

Output:

```123
odd```

## உயிர்/Uyir

```முதன்மை என்பதின் வகை எண் பணி {{
எ இன் வகை எண்{\$5} = 0;
படை வகை சரம்;

"எண்ணைக் கொடுங்கள்? ") ஐ திரை.இடு;

எ = எண்{\$5} ஐ விசை.எடு;

ஒருக்கால் (எ.இருமம்(0) == 1) ஆகில் {
படை = "ஒற்றை";
} இல்லையேல் {
படை = "இரட்டை ";
}

{எ, " ஒரு ", படை, "ப்படை எண் ஆகும்"} என்பதை திரை.இடு;

முதன்மை  = 0;
}};```

## VBA

```4 ways = 4 Functions :
IsEven ==> Use the even and odd predicates
IsEven2 ==> Check the least significant digit. With binary integers, i bitwise-and 1 equals 0 iff i is even
IsEven3 ==> Divide i by 2. The remainder equals 0 if i is even.
IsEven4 ==> Use modular congruences```
```Option Explicit

Sub Main_Even_Odd()
Dim i As Long

For i = -50 To 48 Step 7
Debug.Print i & " : IsEven ==> " & IIf(IsEven(i), "is even", "is odd") _
& " " & Chr(124) & " IsEven2 ==> " & IIf(IsEven2(i), "is even", "is odd") _
& " " & Chr(124) & " IsEven3 ==> " & IIf(IsEven3(i), "is even", "is odd") _
& " " & Chr(124) & " IsEven4 ==> " & IIf(IsEven4(i), "is even", "is odd")
Next
End Sub

Function IsEven(Number As Long) As Boolean
'Use the even and odd predicates
IsEven = (WorksheetFunction.Even(Number) = Number)
End Function

Function IsEven2(Number As Long) As Boolean
'Check the least significant digit.
'With binary integers, i bitwise-and 1 equals 0 iff i is even, or equals 1 iff i is odd.
Dim lngTemp As Long
lngTemp = CLng(Right(CStr(Number), 1))
If (lngTemp And 1) = 0 Then IsEven2 = True
End Function

Function IsEven3(Number As Long) As Boolean
'Divide i by 2.
'The remainder equals 0 if i is even.
Dim sngTemp As Single
sngTemp = Number / 2
IsEven3 = ((Int(sngTemp) - sngTemp) = 0)
End Function

Function IsEven4(Number As Long) As Boolean
'Use modular congruences
IsEven4 = (Number Mod 2 = 0)
End Function
```
Output:
```-50 : IsEven ==> is even | IsEven2 ==> is even | IsEven3 ==> is even | IsEven4 ==> is even
-43 : IsEven ==> is odd | IsEven2 ==> is odd | IsEven3 ==> is odd | IsEven4 ==> is odd
-36 : IsEven ==> is even | IsEven2 ==> is even | IsEven3 ==> is even | IsEven4 ==> is even
-29 : IsEven ==> is odd | IsEven2 ==> is odd | IsEven3 ==> is odd | IsEven4 ==> is odd
-22 : IsEven ==> is even | IsEven2 ==> is even | IsEven3 ==> is even | IsEven4 ==> is even
-15 : IsEven ==> is odd | IsEven2 ==> is odd | IsEven3 ==> is odd | IsEven4 ==> is odd
-8 : IsEven ==> is even | IsEven2 ==> is even | IsEven3 ==> is even | IsEven4 ==> is even
-1 : IsEven ==> is odd | IsEven2 ==> is odd | IsEven3 ==> is odd | IsEven4 ==> is odd
6 : IsEven ==> is even | IsEven2 ==> is even | IsEven3 ==> is even | IsEven4 ==> is even
13 : IsEven ==> is odd | IsEven2 ==> is odd | IsEven3 ==> is odd | IsEven4 ==> is odd
20 : IsEven ==> is even | IsEven2 ==> is even | IsEven3 ==> is even | IsEven4 ==> is even
27 : IsEven ==> is odd | IsEven2 ==> is odd | IsEven3 ==> is odd | IsEven4 ==> is odd
34 : IsEven ==> is even | IsEven2 ==> is even | IsEven3 ==> is even | IsEven4 ==> is even
41 : IsEven ==> is odd | IsEven2 ==> is odd | IsEven3 ==> is odd | IsEven4 ==> is odd
48 : IsEven ==> is even | IsEven2 ==> is even | IsEven3 ==> is even | IsEven4 ==> is even```

## VBScript

```Function odd_or_even(n)
If n Mod 2 = 0 Then
odd_or_even = "Even"
Else
odd_or_even = "Odd"
End If
End Function

WScript.StdOut.Write "Please enter a number: "
WScript.StdOut.Write n & " is " & odd_or_even(CInt(n))
WScript.StdOut.WriteLine
```
Output:
```C:\>cscript /nologo odd_or_even.vbs
Please enter a number: 6
6 is Even

C:\>cscript /nologo odd_or_even.vbs
Please enter a number: 9
9 is Odd

C:\>cscript /nologo odd_or_even.vbs
Please enter a number: -1
-1 is Odd
```

## Verilog

```module main;
integer i;

initial begin
for (i = 1; i <= 10; i = i+1) begin
if (i % 2 == 0) \$display(i, " is even");
else            \$display(i, " is odd");
end
\$finish ;
end
endmodule
```

## Visual Basic .NET

Translation of: FreeBASIC
```Module Module1

Sub Main()
Dim str As String
Dim num As Integer
While True
Console.Write("Enter an integer or 0 to finish: ")
If Integer.TryParse(str, num) Then
If num = 0 Then
Exit While
End If
If num Mod 2 = 0 Then
Console.WriteLine("Even")
Else
Console.WriteLine("Odd")
End If
Else
End If
End While
End Sub

End Module
```

### BigInteger

```Imports System.Numerics

Module Module1
Function IsOdd(bi As BigInteger) As Boolean
Return Not bi.IsEven
End Function

Function IsEven(bi As BigInteger) As Boolean
Return bi.IsEven
End Function

Sub Main()
' uncomment one of the following Dim statements
' Dim x As Byte = 3
' Dim x As Short = 3
' Dim x As Integer = 3
' Dim x As Long = 3
' Dim x As SByte = 3
' Dim x As UShort = 3
' Dim x As UInteger = 3
' Dim x As ULong = 3
' Dim x as BigInteger = 3
' the following three types give a warning, but will work
' Dim x As Single = 3
' Dim x As Double = 3
' Dim x As Decimal = 3

Console.WriteLine("{0} {1}", IsOdd(x), IsEven(x))
End Sub
End Module
```

## Vlang

```fn test(n i64) {
print('Testing integer \$n')

if n&1 == 0 {
print(' even')
}else{
print('  odd')
}

if n%2 == 0 {
println(' even')
}else{
println('  odd')
}
}

fn main(){
test(-2)
test(-1)
test(0)
test(1)
test(2)
}```
Output:
```Testing integer -2 even even
Testing integer -1  odd  odd
Testing integer 0 even even
Testing integer 1  odd  odd
Testing integer 2 even even
```

## WDTE

```let s => import 'stream';
let str => import 'strings';

let evenOrOdd n => (
let even n => == (% n 2) 0;
switch n {
even => 'even';
default => 'odd';
};
);

s.range 10
-> s.map (@ s n => str.format '{} is {}.' n (evenOrOdd n))
-> s.map (io.writeln io.stdout)
-> s.drain;```

## WebAssembly

This solution tests the low bit of the given integer, which is always 0 for even numbers and 1 for odd numbers (including negative numbers).

```(module
;; function isOdd: returns 1 if its argument is odd, 0 if it is even.
(func \$isOdd (param \$n i32) (result i32)
get_local \$n
i32.const 1
i32.and   ;; computes (n & 1), i.e. returns low bit of n
)
(export "isOdd" (func \$isOdd))
)```

## Wren

Library: Wren-fmt
```import "/fmt" for Fmt

var isEven1 = Fn.new { |i| i & 1 == 0 }

var isEven2 = Fn.new { |i| i % 2 == 0 }

var tests = [10, 11, 0,  57,  34,  -23,  -42]
System.print("Tests    : %(Fmt.v("s", -4, tests, 0, " ", ""))")
var res1 = tests.map { |t| isEven1.call(t) ? "even" : "odd" }.toList
System.print("Method 1 : %(Fmt.v("s", -4, res1, 0, " ", ""))")
var res2 = tests.map { |t| isEven2.call(t) ? "even" : "odd" }.toList
System.print("Method 2 : %(Fmt.v("s", -4, res2, 0, " ", ""))")
```
Output:
```Tests    : 10   11   0    57   34   -23  -42
Method 1 : even odd  even odd  even odd  even
Method 2 : even odd  even odd  even odd  even
```

## x86-64 Assembly

```evenOdd:
mov  rax,1
and  rax,rdi
ret```

## XBS

```#>
Typed XBS
evenOrOdd function
true = even
false = odd
<#
func evenOrOdd(a:number=0){
send a%2==0;
}
set arr:array = [0,1,2,3,4,5,6,7,9,10];
foreach(v of arr){
log(v+" is even? "+evenOrOdd(v))
}```
Output:
```0 is even? true
1 is even? false
2 is even? true
3 is even? false
4 is even? true
5 is even? false
6 is even? true
7 is even? false
9 is even? false
10 is even? true
```

## xEec

```>100 p i# jz-1 o# t h#1 ms jz2003 p >0110 h#2 r ms t h#1 ms p
jz1002 h? jz2003 p jn0110 h#10 o\$ p jn100 >2003 p p h#0 h#10
h\$d h\$d h\$o h#32 h\$s h\$i h#32 jn0000 >1002 p p h#0 h#10
h\$n h\$e h\$v h\$e h#32 h\$s h\$i h#32 >0000 o\$ p jn0000 jz100```

## XLISP

XLISP provides EVENP and ODDP, or, if you prefer, EVEN? and ODD?; if one wanted to reimplement them, it could be done like this (or in other ways).

```(defun my-evenp (x)
(= (logand x 1) 0) )

(defun my-oddp (x)
(/= (logand x 1) 0) )
```

## Xojo

```For num As Integer = 1 To 5
If num Mod 2 = 0 Then
MsgBox(Str(num) + " is even.")
Else
MsgBox(Str(num) + " is odd.")
End If
Next
```
Output:
```1 is odd.
2 is even.
3 is odd.
4 is even.
5 is odd.
```

## XPL0

```include c:\cxpl\codes;
int I;
[for I:= -4 to +3 do
[IntOut(0, I);
Text(0, if I&1 then " is odd   " else " is even  ");
Text(0, if rem(I/2)#0 then "odd" else "even");
CrLf(0);
];
]```
Output:
```-4 is even  even
-3 is odd   odd
-2 is even  even
-1 is odd   odd
0 is even  even
1 is odd   odd
2 is even  even
3 is odd   odd
```

## Yabasic

Translation of: Phix
```for i = -5 to 5
print i, and(i,1), mod(i,2)
next```

## Z80 Assembly

Z80 Assembly has a few ways of testing if a number is even or odd:

### RRC

A right rotate will set the carry if the register's value is odd and clear it if it's even. This does alter the contents of the register, so only use this method if you don't need to remember the number being tested after getting the results of the test. This is the fastest way the Z80 can test a value for even or odd, but only when testing the accumulator A

```rrca
jp nc,isEven
```

### AND

`AND 1` will change the accumulator to 1 if its value was odd, and 0 if its value was even. If you want to selectively load a 0 or 1 into the accumulator based on whether a variable is odd or even, this is the best way to do so. Like the `RRC` method, this test is destructive, so if you need to preserve the original value of the accumulator after the test, use the method below instead.

```and &01
jp z,isEven
```

### BIT

This method is the slowest, but it doesn't change the value in the register being tested. It works on any 8 bit register, (HL), (IX+#), or (IY+#), making it the most versatile. Although I say it's the slowest, the difference is so small and the execution time so fast that you'd never notice anyway. The Z80 can perform all these tests faster than you can blink!

```bit 0,c
jp z,C_IS_EVEN
```

## zkl

`[-3..4].pump(fcn(n){ println(n," is ",n.isEven and "even" or "odd") })`

Ints have isEven and isOdd properties. pump, in this case, is the same as apply/map without aggregating a result.

Output:
```-3 is odd
-2 is even
-1 is odd
0 is even
1 is odd
2 is even
3 is odd
4 is even
```
`[-3..4].apply("isEven").println();`
Output:
`L(False,True,False,True,False,True,False,True)`

## Zoea

```program: even_or_odd
case: 1
input: 2
output: even
case: 2
input: 4
output: even
case: 3
input: 1
output: odd
case: 4
input: 7
output: odd```

## zonnon

```module Main;
var
x: integer;
s: set;
begin
x := 10;writeln(x:3," is odd?",odd(x));
s := set(s);writeln(x:3," is odd?",0 in s); (* check right bit *)
x := 11;writeln(x:3," is odd?",odd(x));
s := set(x);writeln(x:3," is odd?",0 in s); (* check right bit *)
end Main.```
Output:
``` 10 is odd? false
10 is odd? false
11 is odd?  true
11 is odd?  true
```

## ZX Spectrum Basic

```10 FOR n=-3 TO 4: GO SUB 30: NEXT n
20 STOP
30 LET odd=FN m(n,2)
40 PRINT n;" is ";("Even" AND odd=0)+("Odd" AND odd=1)
50 RETURN
60 DEF FN m(a,b)=a-INT (a/b)*b
```