Loops/Do-while
You are encouraged to solve this task according to the task description, using any language you may know.
Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once.
- Related tasks
- Loop over multiple arrays simultaneously
- Loops/Break
- Loops/Continue
- Loops/Do-while
- Loops/Downward for
- Loops/For
- Loops/For with a specified step
- Loops/Foreach
- Loops/Increment loop index within loop body
- Loops/Infinite
- Loops/N plus one half
- Loops/Nested
- Loops/While
- Loops/with multiple ranges
- Loops/Wrong ranges
- Reference
- Do while loop Wikipedia.
11l
11l doesn't have a do-while loop.
V val = 0
L
val++
print(val)
I val % 6 == 0
L.break
360 Assembly
- Basic
The WTO macro is in SYS1.MACLIB, which needs to be in the SYSLIB concatenation at assembly.
* Do-While
DOWHILE CSECT , This program's control section
BAKR 14,0 Caller's registers to linkage stack
LR 12,15 load entry point address into Reg 12
USING DOWHILE,12 tell assembler we use Reg 12 as base
XR 9,9 clear Reg 9 - divident value
LA 6,6 load divisor value 6 in Reg 6
LA 8,WTOLEN address of WTO area in Reg 8
LOOP DS 0H
LA 9,1(,9) add 1 to divident Reg 9
ST 9,FW2 store it
LM 4,5,FDOUBLE load into even/odd register pair
STH 9,WTOTXT store divident in text area
MVI WTOTXT,X'F0' first of two bytes zero
OI WTOTXT+1,X'F0' make second byte printable
WTO TEXT=(8) print it (Write To Operator macro)
DR 4,6 divide Reg pair 4,5 by Reg 6
LTR 5,5 test quotient (remainder in Reg 4)
BNZ RETURN if one: 6 iterations, exit loop.
B LOOP if zero: loop again.
RETURN PR , return to caller.
FDOUBLE DC 0FD
DC F'0'
FW2 DC F'0'
WTOLEN DC H'2' fixed WTO length of two
WTOTXT DC CL2' '
END DOWHILE
- Structured Macros
Although specified at the beginning (DO UNTIL), the test is done at the end of the loop (ENDDO). Structured macros (DO ENDDO) weren't in the 1963 standard of Assembler 360, but there are part of it since since 1998.
* Do-While 27/06/2016
DOWHILE CSECT
USING DOWHILE,12 set base register
LR 12,15 init base register
SR 6,6 v=0
LA 4,1 init reg 4
DO UNTIL=(LTR,4,Z,4) do until v mod 6=0
LA 6,1(6) v=v+1
STC 6,WTOTXT v
OI WTOTXT,X'F0' make editable
WTO MF=(E,WTOMSG) display v
LR 4,6 v
SRDA 4,32 shift dividend to reg 5
D 4,=F'6' v/6 so r4=remain & r5=quotient
ENDDO , end do
BR 14 return to caller
WTOMSG DS 0F full word alignment for wto
WTOLEN DC AL2(L'WTOTXT+4) length of WTO buffer
DC H'0' must be zero
WTOTXT DS C one char
END DOWHILE
6502 Assembly
Code is called as a subroutine (i.e. JSR DoWhileSub). Specific OS/hardware routines for printing are left unimplemented.
DoWhileSub: PHA
TYA
PHA ;push accumulator and Y register onto stack
LDY #0
DoWhileLoop: INY
JSR DisplayValue ;routine not implemented
TYA
SEC
Modulus: SBC #6
BCS Modulus
ADC #6
BNE DoWhileLoop
PLA
TAY
PLA ;restore Y register and accumulator from stack
RTS ;return from subroutine
AArch64 Assembly
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program loopdowhile64.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
/*********************************/
/* Initialized data */
/*********************************/
.data
szMessResult: .asciz "Counter = @ \n" // message result
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
sZoneConv: .skip 24
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: // entry of program
mov x20,0 // indice
mov x21,6
1: // begin loop
mov x0,x20
ldr x1,qAdrsZoneConv // conversion value value
bl conversion10 // decimal
ldr x0,qAdrszMessResult
ldr x1,qAdrsZoneConv // display conversion
bl strInsertAtCharInc // insert result at @ character
bl affichageMess // display message
add x20,x20,1 // increment counter
udiv x0,x20,x21 // divide by 6
msub x1,x0,x21,x20 // compute remainder
cbnz x1,1b // loop if remainder <> zéro
100: // standard end of the program
mov x0,0 // return code
mov x8,EXIT // request to exit program
svc 0 // perform the system call
qAdrsZoneConv: .quad sZoneConv
qAdrszMessResult: .quad szMessResult
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
Action!
Proc Main()
byte A
A=0
Do
A==+1
PrintBE(A)
Until A Mod 6=0
Od
Return
ActionScript
var val:int = 0;
do
{
trace(++val);
} while (val % 6);
Ada
loop
Value := Value + 1;
Put (Value);
exit when Value mod 6 = 0;
end loop;
Here is an alternative version:
for Value in 0..Integer'Last loop
Put (Value);
exit when Value mod 6 = 0;
end loop;
Agena
Tested with Agena 2.9.5 Win32
scope
local i := 0;
do
inc i, 1;
print( i )
as ( i % 6 ) <> 0
epocs
Aime
integer a;
a = 0;
do {
a += 1;
o_integer(a);
o_byte('\n');
} while (a % 6 != 0);
ALGOL 60
No structured control instructions in Algol 60 to perform this task. Use of 2 harmful GOTOs. I agree Edsger Dijkstra communication "Go To Statement Considered Harmful", ACM 1968.
'BEGIN' 'COMMENT' Loops DoWhile - Algol60 - 22/06/2018;
'INTEGER' I;
I:=0;
LOOP:
I:=I+1;
OUTINTEGER(1,I);
'IF' I=I'/'6*6 'THEN' 'GOTO' ENDLOOP;
'GOTO' LOOP;
ENDLOOP:
'END'
- Output:
+1 +2 +3 +4 +5 +6
A "goto-less" approach
While a judicious "goto" may sometimes be clearer than the alternative, it is possible to avoid it in this case by using the for-while statement and a boolean flag to implement a test-at-the-bottom loop.
begin
integer i;
boolean another;
i := 0;
another := true;
for i := i while another do
begin
i := i + 1;
outinteger(1,i);
comment - stop once i mod 6 = 0;
if i = (i div 6) * 6 then another := false;
end;
end
- Output:
1 2 3 4 5 6
ALGOL 68
FOR value WHILE
print(value);
# WHILE # value MOD 6 /= 0 DO
SKIP
OD
ALGOL W
begin
integer i;
i := 0;
while
begin
i := i + 1;
write( i );
( i rem 6 ) not = 0
end
do begin end
end.
AmigaE
PROC main()
DEF i = 0
REPEAT
i := i + 1
WriteF('\d\n', i)
UNTIL Mod(i, 6) = 0
ENDPROC
ARM Assembly
/* ARM assembly Raspberry PI */
/* program loopdowhile.s */
/* Constantes */
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
/*********************************/
/* Initialized data */
/*********************************/
.data
szMessResult: .ascii "Counter = " @ message result
sMessValeur: .fill 12, 1, ' '
.asciz "\n"
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
/*********************************/
/* code section */
/*********************************/
.text
.global main
main: @ entry of program
push {fp,lr} @ saves 2 registers
mov r4,#0
1: @ begin loop
mov r0,r4
ldr r1,iAdrsMessValeur @ display value
bl conversion10 @ call function with 2 parameter (r0,r1)
ldr r0,iAdrszMessResult
bl affichageMess @ display message
add r4,#1 @ increment counter
mov r0,r4
mov r1,#6 @ division conuter by 6
bl division
cmp r3,#0 @ remainder = zéro ?
bne 1b @ no ->begin loop one
100: @ standard end of the program
mov r0, #0 @ return code
pop {fp,lr} @restaur 2 registers
mov r7, #EXIT @ request to exit program
svc #0 @ perform the system call
iAdrsMessValeur: .int sMessValeur
iAdrszMessResult: .int szMessResult
/******************************************************************/
/* display text with size calculation */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {r0,r1,r2,r7,lr} @ save registres
mov r2,#0 @ counter length
1: @ loop length calculation
ldrb r1,[r0,r2] @ read octet start position + index
cmp r1,#0 @ if 0 its over
addne r2,r2,#1 @ else add 1 in the length
bne 1b @ and loop
@ so here r2 contains the length of the message
mov r1,r0 @ address message in r1
mov r0,#STDOUT @ code to write to the standard output Linux
mov r7, #WRITE @ code call system "write"
svc #0 @ call systeme
pop {r0,r1,r2,r7,lr} @ restaur des 2 registres */
bx lr @ return
/******************************************************************/
/* Converting a register to a decimal */
/******************************************************************/
/* r0 contains value and r1 address area */
conversion10:
push {r1-r4,lr} @ save registers
mov r3,r1
mov r2,#10
1: @ start loop
bl divisionpar10 @ r0 <- dividende. quotient ->r0 reste -> r1
add r1,#48 @ digit
strb r1,[r3,r2] @ store digit on area
sub r2,#1 @ previous position
cmp r0,#0 @ stop if quotient = 0 */
bne 1b @ else loop
@ and move spaces in first on area
mov r1,#' ' @ space
2:
strb r1,[r3,r2] @ store space in area
subs r2,#1 @ @ previous position
bge 2b @ loop if r2 >= zéro
100:
pop {r1-r4,lr} @ restaur registres
bx lr @return
/***************************************************/
/* division par 10 signé */
/* Thanks to http://thinkingeek.com/arm-assembler-raspberry-pi/*
/* and http://www.hackersdelight.org/ */
/***************************************************/
/* r0 dividende */
/* r0 quotient */
/* r1 remainder */
divisionpar10:
/* r0 contains the argument to be divided by 10 */
push {r2-r4} /* save registers */
mov r4,r0
mov r3,#0x6667 @ r3 <- magic_number lower
movt r3,#0x6666 @ r3 <- magic_number upper
smull r1, r2, r3, r0 @ r1 <- Lower32Bits(r1*r0). r2 <- Upper32Bits(r1*r0)
mov r2, r2, ASR #2 /* r2 <- r2 >> 2 */
mov r1, r0, LSR #31 /* r1 <- r0 >> 31 */
add r0, r2, r1 /* r0 <- r2 + r1 */
add r2,r0,r0, lsl #2 /* r2 <- r0 * 5 */
sub r1,r4,r2, lsl #1 /* r1 <- r4 - (r2 * 2) = r4 - (r0 * 10) */
pop {r2-r4}
bx lr /* leave function */
/***************************************************/
/* integer division unsigned */
/***************************************************/
division:
/* r0 contains dividend */
/* r1 contains divisor */
/* r2 returns quotient */
/* r3 returns remainder */
push {r4, lr}
mov r2, #0 @ init quotient
mov r3, #0 @ init remainder
mov r4, #32 @ init counter bits
b 2f
1: @ loop
movs r0, r0, LSL #1 @ r0 <- r0 << 1 updating cpsr (sets C if 31st bit of r0 was 1)
adc r3, r3, r3 @ r3 <- r3 + r3 + C. This is equivalent to r3 ? (r3 << 1) + C
cmp r3, r1 @ compute r3 - r1 and update cpsr
subhs r3, r3, r1 @ if r3 >= r1 (C=1) then r3 ? r3 - r1
adc r2, r2, r2 @ r2 <- r2 + r2 + C. This is equivalent to r2 <- (r2 << 1) + C
2:
subs r4, r4, #1 @ r4 <- r4 - 1
bpl 1b @ if r4 >= 0 (N=0) then loop
pop {r4, lr}
bx lr
AppleScript
on printConsole(x)
return x as string
end printConsole
set {i, table} to {0, {return}}
repeat while (i mod 6 is not 0 or i is not 6)
set i to i + 1
set end of table to i & return
printConsole(table)
end repeat
- Output:
" 1 2 3 4 5 6 "
Arturo
value: 0
until [
value: value + 1
print value
] [ 0 = value%6 ]
- Output:
1 2 3 4 5 6
Asymptote
Asymptote's control structures are similar to those in C, C++, or Java
int i = 0;
do {
++i;
write(" ", i, suffix=none);
} while (i % 6 != 0);
AutoHotkey
While mod(A_Index, 6) ;comment:everything but 0 is considered true
output = %output%`n%A_Index%
MsgBox % output
AWK
BEGIN {
val = 0
do {
val++
print val
} while( val % 6 != 0)
}
Axe
While Axe does not have explicit do-while loops, they can be easily emulated using an infinite loop with a conditional terminator:
0→A
While 1
A++
Disp A▶Dec,i
End!If A^6
BASIC
Applesoft BASIC
0 REMADE FOR DO WHILE
1 DEF FN MOD6(N) = N - INT (N / 6) * 6
2 LET V4LUE = 0
3 FOR DO = 0 TO 1
10 LET V4LUE = V4LUE + 1
20 PRINT V4LUE" ";
30 WHILE = FN MOD6(V4LUE) < > 0:DO = NOT WHILE: NEXT
ASIC
ASIC does not have a do .. while
construct. Equivalent using WHILE
:
REM Loops/Do-while
I = 0
REM first iteration - before the While
I = I + 1
PRINT I
IMod6 = I MOD 6
WHILE IMod6 <> 0
I = I + 1
PRINT I
IMod6 = I MOD 6
WEND
END
- Output:
1 2 3 4 5 6
Equivalent using conditional jump:
REM Loops/Do-while
I = 0
LoopStart:
I = I + 1
PRINT I
IMod6 = I MOD 6
IF IMod6 <> 0 THEN LoopStart:
END
- Output:
As above
BaCon
a=0
REPEAT
INCR a
PRINT a
UNTIL MOD(a,6) == 0
BASIC256
i = 0
do
i += 1
print i; " ";
until i mod 6 = 0
print
end
BBC BASIC
a = 0
REPEAT
a = a + 1
PRINT a
UNTIL a MOD 6 = 0
Chipmunk Basic
In Chipmunk Basic Man Page, the words do
, loop
, and until
are mentioned as reserved, but the do .. loop until
statement is not described, probably because of uncorrected abnormal behavior of the interpreter. In case of such behavior you may use equivalents (e.g. with while .. wend
).
100 rem Loops/Do-while
110 i = 0
120 do
130 i = i+1
140 print i
150 loop until i mod 6 = 0
160 end
- Output:
1 2 3 4 5 6
Commodore BASIC
50 rem does not have do-while simultate using for-next
100 x=0
120 for b=-1 to 0 step 0
130 x=x+1
140 print x
150 b=x/6<>int(x/6)
160 next x
FreeBASIC
' FB 1.05. 0 Win64
Dim i As Integer = 0
Do
i += 1
Print i; " ";
Loop While i Mod 6 <> 0
Print
Sleep
- Output:
1 2 3 4 5 6
Gambas
Click this link to run this code
Public Sub Main()
Dim siCount As Short
Repeat
Inc siCount
Print siCount;;
Until siCount Mod 6 = 0
End
- Output:
1 2 3 4 5 6
GW-BASIC
GW-BASIC does not have a do .. while
construct.
Equivalent using WHILE
:
10 LET I% = 0
20 ' first iteration - before the WHILE
30 LET I% = I% + 1
40 PRINT I%
50 WHILE I% MOD 6 <> 0
60 LET I% = I% + 1
70 PRINT I%
80 WEND
Equivalent using GOTO
:
10 LET I% = 0
20 LET I% = I% + 1
30 PRINT I%
40 IF I% MOD 6 <> 0 THEN GOTO 20
IS-BASIC
100 LET I=0
110 DO
120 LET I=I+1
130 PRINT I
140 LOOP UNTIL MOD(I,6)=0
Liberty BASIC
a = 0
do
a = a + 1
print a
loop until (a mod 6) = 0
See also QBasic.
Microsoft Small Basic
Microsoft Small Basic does not have a do .. while
construct.
Equivalent using While
:
i = 0
' first iteration - before the While
i = i + 1
TextWindow.WriteLine(i)
While Math.Remainder(i, 6) <> 0
i = i + 1
TextWindow.WriteLine(i)
EndWhile
Equivalent using Goto
:
i = 0
loopStart:
i = i + 1
TextWindow.WriteLine(i)
If Math.Remainder(i, 6) <> 0 Then
Goto loopStart
EndIf
Minimal BASIC
Minimal BASIC does not have a do .. while
construct. Equivalent using conditional jump:
10 REM Loops/Do-while
20 LET I=0
30 LET I=I+1
40 PRINT I
50 IF INT(I/6)*6 <> I THEN 30
60 END
MSX Basic
The Minimal BASIC solution works without any changes.
NS-HUBASIC
10 PRINT "NO,"A" ISN'T A MULTIPLE OF 6."
20 A=A+1
30 IF A-(A/6)*6<>0 THEN GOTO 10
40 PRINT "YES, 6 IS A MULTIPLE OF 6."
PureBasic
x=0
Repeat
x+1
Debug x
Until x%6=0
QB64
CBTJD: 2020/03/14
DO
PRINT n
n = n + 1
LOOP WHILE n MOD 6 <> 0
'Another demo of DO loops
Dim As Integer Counter
Print "First loop DO..LOOP UNTIL"
Counter = 0
Do
Print Counter
Counter = Counter + 1
Loop Until Counter Mod 6 = 0
Print "Counter Mod 6 = "; Counter Mod 6
Print "First loop DO WHILE..LOOP"
Counter = 1
Do While Counter Mod 6 <> 0
Print Counter
Counter = Counter + 1
Loop
Print "Counter Mod 6 = "; Counter Mod 6
End
QBasic
a = 0
DO
a = a + 1
PRINT a;
LOOP WHILE a MOD 6 <> 0
Quite BASIC
The Minimal BASIC solution works without any changes.
Run BASIC
Run Basic does not have a do .. while
construct. Equivalent using conditional jump:
i = 0
[start]
i = i +1
print i; " ";
if i mod 6 <> 0 then [start]
Sinclair ZX81 BASIC
10 LET X=0
20 LET X=X+1
30 PRINT X
40 IF X/6<>INT (X/6) THEN GOTO 20
SmallBASIC
repeat
v++
print v
until(v mod 6 == 0)
Tiny BASIC
Tiny Basic does not have a do .. while
construct. Equivalent using conditional jump:
10 REM Loops/Do-while
20 LET I = 0
30 LET I = I + 1
40 PRINT I
50 IF (I / 6) * 6 <> I THEN GOTO 30
60 END
- Output:
1 2 3 4 5 6
True BASIC
LET i = 0
DO
LET i = i + 1
PRINT i; " ";
LOOP WHILE REMAINDER(i, 6) <> 0
PRINT
END
VBA
Public Sub LoopDoWhile()
Dim value As Integer
value = 0
Do
value = value + 1
Debug.Print value;
Loop While value Mod 6 <> 0
End Sub
- Output:
1 2 3 4 5 6
Visual Basic .NET
Dim i = 0
Do
i += 1
Console.WriteLine(i)
Loop Until i Mod 6 = 0
XBasic
PROGRAM "dowhile"
DECLARE FUNCTION Entry()
FUNCTION Entry()
val% = 0
DO
INC val%
PRINT val%
LOOP WHILE val% MOD 6 <> 0 ' or LOOP UNTIL val% MOD 6 = 0
END FUNCTION
END PROGRAM
Yabasic
i = 0
repeat
i = i + 1
print i, " ";
until mod(i, 6) = 0
print
bc
i = 0
for (;;) {
++i /* increments then prints i */
if (i % 6 == 0) break
}
quit
Befunge
0>1+:.v
|%6: <
@
C
int val = 0;
do{
val++;
printf("%d\n",val);
}while(val % 6 != 0);
C#
int a = 0;
do
{
a += 1;
Console.WriteLine(a);
} while (a % 6 != 0);
C++
int val = 0;
do{
val++;
std::cout << val << std::endl;
}while(val % 6 != 0);
C3
In this example we use default zero initialization of locals in C3.
int val;
do
{
io::printn(++val);
}
while (val % 6 != 0);
Chapel
var val = 0;
do {
val += 1;
writeln(val);
} while val % 6 > 0;
ChucK
0 => int value;
do
{
value++;
<<<value>>>;
}
while(value % 6 != 0);
Clipper
Local n := 0
DO WHILE .T.
? ++n
IF n % 6 == 0
EXIT
ENDIF
ENDDO
Clojure
(loop [i 0]
(let [i* (inc i)]
(println i*)
(when-not (zero? (mod i* 6))
(recur i*))))
COBOL
The COBOL equivalent of a do-while loop is PERFORM WITH TEST AFTER UNTIL some-condition
.
IDENTIFICATION DIVISION.
PROGRAM-ID. loop-do-while.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 i PIC 99 VALUE 0.
PROCEDURE DIVISION.
PERFORM WITH TEST AFTER UNTIL FUNCTION MOD(i, 6) = 0
ADD 1 TO i
DISPLAY i
END-PERFORM
GOBACK
.
Coco
Do-while loops are a JavaScript feature removed in CoffeeScript but re-added in Coco.
v = 0
do
console.log ++v
while v % 6
CoffeeScript
CoffeeScript doesn't have do {} while ()
loop, but it can be emulated using loop
statement and break unless
statement.
val = 0
loop
console.log ++val
break unless val % 6
ColdFusion
<cfscript>
value = 0;
do
{
value += 1;
writeOutput( value );
} while( value % 6 != 0 );
</cfscript>
Common Lisp
(let ((val 0))
(loop do
(incf val)
(print val)
while (/= 0 (mod val 6))))
loop can set up temporary values, and incf returns a value, so it's also possible to do
(loop with val = 0
do (print (incf val))
until (= 0 (mod val 6)))
Using DO
(do* ((a 0) ; Initialize to 0
(b (incf a) (incf b))) ; Set first increment and increment on every loop
((zerop (mod b 6)) (print b)) ; Break condition and print last value `6' (right?)
(print b)) ; On every loop print value
- Output:
1 2 3 4 5 6
D
import std.stdio;
void main() {
int val;
do {
val++;
write(val, " ");
} while (val % 6 != 0);
}
- Output:
1 2 3 4 5 6
Dart
void main() {
int val = 0;
do {
val++;
print(val);
} while (val % 6 != 0);
}
dc
0 si [i = 0]sz
[2Q]sA [A = code to break loop]sz
[
li 1 + p [print it = i + 1]sz
d si [i = it, leave it on stack]sz
6 % 0 =A [call A if 0 == it % 6]sz
0 0 =B [continue loop]sz
]sB 0 0 =B
Delphi
program Loop;
{$APPTYPE CONSOLE}
var
I: Integer;
begin
I:= 0;
repeat
Inc(I);
Write(I:2);
until I mod 6 = 0;
Writeln;
Readln;
end.
Draco
proc nonrec main() void:
byte i;
i := 0;
while
i := i + 1;
write(i:2);
i % 6 ~= 0
do od
corp
- Output:
1 2 3 4 5 6
Dragon
val = 0
do{
val++
showln val
}while(val % 6 != 0)
DuckDB
DuckDB's iterative control structure is the recursive CTE (Common Table Expression), which checks the initial condition before iterating, so in the following, the first increment is performed unconditionally.
create or replace function do_while(init) as table (
with recursive cte as (
select init+1 as value -- Increment unconditionally
union all -- Loop
select value+1 as value -- Each time through the loop, add 1 to the value then print it.
from cte
where value % 6 != 0 -- "while value mod 6 is not equal to 0"
)
from cte order by value
);
# The task
from do_while(0);
# Also check that the loop executes at least once.
from do_while(-1);
- Output:
┌───────┐ │ value │ │ int32 │ ├───────┤ │ 1 │ │ 2 │ │ 3 │ │ 4 │ │ 5 │ │ 6 │ └───────┘ ┌───────┐ │ value │ │ int32 │ ├───────┤ │ 0 │ └───────┘
DUP
DUP only provides a while loop in the form of [condition][block]#
, where the block is executed in a loop as long as the condition is nonzero/true.
A do-while loop is technically nothing more than executing the block once before running an ordinary while loop, so we simply define an operator or function that contains the block (comments in curly braces):
[1+$.' ,]⇒A {operator definition: PUSH 1, ADD, DUP, print top of stack to SDTOUT, print whitespace}
[1+$.' ,]a: {function definition}
and put the defined block in front of the while loop, and inside the while loop itself:
If the block was defined as an operator, the whole program would look like this (comments in curly braces):
[1+$.' ,]⇒A
0 A[$6/%][A]# {PUSH 0, execute operator A, [DUP, PUSH 6, MOD/DIV, POP][execute operator A]#}
And if the block is defined as a named function:
[1+$.' ,]a:
0 a;![$6/%][a;!]#
Result:
1 2 3 4 5 6
DWScript
var i := 0;
repeat
Inc(i);
PrintLn(i);
until i mod 6 = 0;
Bold text
Dyalect
var x = 0
do
{
x += 1
print(x)
} while x % 6 != 0
E
E does not have an official do-while construct, but the primitive which loops are built out of (which calls a function which returns a boolean indicating whether it should be called again) can be used to construct a do-while.
var x := 0
__loop(fn {
x += 1
println(x)
x % 6 != 0 # this is the return value of the function
})
EasyLang
value = 0
repeat
value += 1
print value
until value mod 6 = 0
.
Ela
open monad io
loop n | n % 6 == 0 = do return ()
| else = do
putStrLn (show n)
loop (n+1)
_ = loop 10 ::: IO
Elixir
defmodule Loops do
def do_while(n) do
n1 = n + 1
IO.puts n1
if rem(n1, 6) == 0, do: :ok,
else: do_while(n1)
end
end
Loops.do_while(0)
Emacs Lisp
The condition form for while
can be a progn
to evaluate arbitrary code before the loop condition. The body of a while
can be empty.
(let ((val 0))
(while (progn
(setq val (1+ val))
(message "%d" val)
(/= 0 (mod val 6)))))
Alternatively, the loop can be rewritten to check for the exit condition and fulfill it at the end of the loop body.
(let ((val 0) done)
(while (not done)
(setq val (1+ val))
(message "%d" val)
(setq done (zerop (mod val 6)))))
Erlang
do() ->
do(0).
do(0) ->
io:fwrite( "0 " ),
do( 1 );
do(N) when N rem 6 =:= 0 ->
io:format("~w~n", [N]);
do(N) ->
io:fwrite( "~p ", [N] ),
do(N+1).
ERRE
A=0
REPEAT
A=A+1
PRINT(A)
UNTIL A MOD 6=0 !UNTIL A-6*INT(A/6)=0 for C-64
Euphoria
include std/console.e
include std/math.e
atom x = 0
loop do
x += 1
?x
until(mod(x,6)) = 0
end loop
if getc(0) then end if
F#
If you must have a loop then this is acceptable F#
let rec loop n =
printfn "%d " n
if (n+1)%6 > 0 then loop (n+1)
loop 0
But I prefer this way:
Seq.initInfinite id |> Seq.takeWhile(fun n->n=0 || n%6>0) |> Seq.iter (fun n-> printfn "%d" n)
Either produces:
- Output:
0 1 2 3 4 5
Many of the solutions to this task show no output in spite of it being required in the task dexcription, so who knows what they do? Of some that have output they think it should be 1 to 6, who can tell from the task description? The following produces 1..6.
// Loops/Do-while. Nigel Galloway: February 14th., 2022
Seq.unfold(fun n->match n with Some n->let n=n+1 in Some(n,if n%6=0 then None else Some(n)) |_->None)(Some 0)|>Seq.iter(printfn "%d")
- Output:
1 2 3 4 5 6
Factor
0 [ dup 6 mod 0 = not ] [ [ . ] [ 1 + ] bi ] do while drop
Fantom
There is no do-while statement in Fantom, so instead use an infinite while loop with a break statement:
class Main
{
public static Void main ()
{
i := 0
while (true)
{
i += 1
echo (i)
if (i % 6 == 0) break // end loop on condition
}
}
}
Forth
: do-until
0
begin 1+
dup .
dup 6 mod 0=
until
drop ;
Fortran
INTEGER :: i = 0
DO
i = i + 1
WRITE(*, *) i
IF (MOD(i, 6) == 0) EXIT
END DO
PROGRAM DOWHILE
C Initialize modulus and value.
INTEGER MODLUS, IVALUE
PARAMETER (MODLUS = 6)
IVALUE = 0
C FORTRAN 77 has no do-while structure -- not semantically. It is not
C difficult to simulate it using GOTO, however:
10 CONTINUE
IVALUE = IVALUE + 1
WRITE (*,*) IVALUE
IF (.NOT. (MOD(IVALUE, MODLUS) .EQ. 0)) GOTO 10
STOP
END
IVALUE = 0
10 CONTINUE
IVALUE=IVALUE+1
WRITE(6,301) IVALUE
301 FORMAT(I5)
IF(MOD(IVALUE,6).NE.0) GOTO 10
END
IVALUE = 0
10 IVALUE=IVALUE+1
WRITE 301,IVALUE
301 FORMAT(I5)
IF(IVALUE-IVALUE/6*6) 10,20,10
20 STOP
END
Fortress
Due to the way that Fortress works, you have to use a label to escape a loop upon a specified condition being met. There is no traditional break
equivalent.
component loops_do_while
export Executable
var x:ZZ32 = 0
run() = label loop
while true do
x += 1
println(x)
if (x MOD 6) = 0
then exit loop
end
end
end loop
end
- Output:
1 2 3 4 5 6
Frink
n = 0
do
{
n = n + 1
println[n]
} while n mod 6 != 0
FutureBasic
window 1
dim as long i
do
i++
print i
until ( i mod 6 == 0 )
HandleEvents
- Output:
1 2 3 4 5 6
GAP
n := 0;
repeat
n := n + 1;
Print(n, "\n");
until RemInt(n, 6) = 0;
GML
i = 0
do
{
i += 1
show_message(string(i))
}
until (i mod 6 = 0)
Go
There is no explicit do-while in Go, but it can be simulated with a range-based for loop and the break statement.
package main
import "fmt"
func main() {
var value int
for {
value++
fmt.Println(value)
if value%6 != 0 {
break
}
}
}
- Output:
1 2 3 4 5 6
It can also be simulated without using a break statement as follows:
package main
import "fmt"
func main() {
var value int
for ok := true; ok; ok = value%6 != 0 {
value++
fmt.Println(value)
}
}
- Output:
Same as before.
package main import "fmt" func main() { // do-while loop 1 n1 := 2 for n1 < 6 { n1 *= 2 } fmt.Println(n1) // prt 8 // do-while loop 2 n2 := 2 for ok := true; ok; ok = n2%8 != 0 { n2 *= 2 } fmt.Println(n2) // prt 8 // do-while loop 3 n3 := 2 for { n3 *= 2 if n3 >= 6 { break } } fmt.Println(n3) // prt 8 }
Groovy
For Groovy 3.0.0 and later.
def i = 0
do {
i++
println i
} while (i % 6 != 0)
Previous versions of Groovy did not have a bottom-checking loop construct. Workaround is to use an "infinite" while loop with a conditional break as the last statement.
def i = 0
while (true) {
i++
println i
if (i % 6 == 0) break
}
- Output:
1 2 3 4 5 6
Harbour
LOCAL n := 0
DO WHILE .T.
? ++n
IF n % 6 == 0
EXIT
ENDIF
ENDDO
Haskell
import Data.List
import Control.Monad
import Control.Arrow
doWhile p f n = (n:) $ takeWhile p $ unfoldr (Just.(id &&& f)) $ succ n
Example executed in GHCi:
*Main> mapM_ print $ doWhile ((/=0).(`mod`6)) succ 0
0
1
2
3
4
5
The standard Prelude also includes, without further import or definition, an until function, which takes three arguments – a predicate function, a transformation function, and an initial value.
main :: IO ()
main =
mapM_ print . reverse $
until
(\(x:_) -> (x > 0) && (mod x 6 == 0))
(\xs@(x:_) -> succ x : xs)
[0]
- Output:
0 1 2 3 4 5 6
With mutable references
Using iterateWhile from monad-loops package
import Data.IORef
import Control.Monad.Loops
main = do
x <- newIORef 0;
iterateWhile (\val -> val `mod` 6 /= 0 ) $ do
modifyIORef x (+1)
val <- readIORef x
print val
return val
Haxe
var val = 0;
do {
val++;
Sys.println(val);
} while( val % 6 != 0);
HolyC
U8 i = 0;
do {
i++;
Print("%d\n", i);
} while (i % 6 != 0);
Icon and Unicon
Icon and Unicon do not have a do-while looping control with end of loop checking. There are four looping controls 'every', 'repeat', 'until', and 'while' (see Introduction to Icon and Unicon/Looping Controls for more information.)
J
J is array-oriented, so there is very little need for loops. For example, one could satisfy this task this way:
,.([^:(0=6|])>:)^:a: 0
0
1
2
3
4
5
This could also be accomplished using Z: to provide early termination from a fold:
0#]F.(>: [ echo [ _2 Z: * * 0=6|]) 0
0
1
2
3
4
5
J does support loops for those times they can't be avoided (just like many languages support gotos for those time they can't be avoided).
3 : 0 ] 0
NB. The 'st' in 'whilst' stands for 'skip test'
whilst. 0 ~: 6 | y do.
y 1!:2 ]2
y =. y+1
end.
i.0 0
)
Though it's rare to see J code like this.
Java
int val = 0;
do{
val++;
System.out.println(val);
}while(val % 6 != 0);
JavaScript
Javascript: Imperative
var val = 0;
do {
print(++val);
} while (val % 6);
Javascript: Functional
ES5
In a functional idiom of JavaScript we cannot use a Do While statement, as it returns no value and is not a composable expression. We can, however achieve the same effect with a composable doWhile function, which takes three arguments, and returns the output series as a value.
- An initial value,
- a Do function which transforms that value repetitively, corresponding to the body of the loop,
- and a conditional While function.
function doWhile(varValue, fnBody, fnTest) {
'use strict';
var d = fnBody(varValue); // a transformed value
return fnTest(d) ? [d].concat(
doWhile(d, fnBody, fnTest)
) : [d];
}
console.log(
doWhile(0, // initial value
function (x) { // Do body, returning transformed value
return x + 1;
},
function (x) { // While condition
return x % 6;
}
).join('\n')
);
Output:
1
2
3
4
5
6
Alternatively, if we assume instead that the unstated problem was not to produce repetitive computation, but to derive the membership of a set we could interpret the task as a request for a JavaScript implementation of the takeWhile function – a familiar staple of functional list processing.
So, for example, something like:
function range(m, n) {
'use strict';
return Array.apply(null, Array(n - m + 1)).map(
function (x, i) {
return m + i;
}
);
}
function takeWhile(lst, fnTest) {
'use strict';
var varHead = lst.length ? lst[0] : null;
return varHead ? (
fnTest(varHead) ? [varHead].concat(
takeWhile(lst.slice(1), fnTest)
) : []
) : []
}
console.log(
takeWhile(
range(1, 100),
function (x) {
return x % 6;
}
).join('\n')
);
Output:
1
2
3
4
5
ES6
A process or value of this kind might be better expressed (in functionally composed JavaScript) with an unfold or until function, returning a list.
(() => {
'use strict';
// unfoldr :: (b -> Maybe (a, b)) -> b -> [a]
function unfoldr(mf, v) {
for (var lst = [], a = v, m;
(m = mf(a)) && m.valid;) {
lst.push(m.value), a = m.new;
}
return lst;
}
// until :: (a -> Bool) -> (a -> a) -> a -> a
function until(p, f, x) {
let v = x;
while(!p(v)) v = f(v);
return v;
}
let result1 = unfoldr(
x => {
return {
value: x,
valid: (x % 6) !== 0,
new: x + 1
}
},
1
);
let result2 = until(
m => (m.n % 6) === 0,
m => {
return {
n : m.n + 1,
xs : m.xs.concat(m.n)
};
},
{
n: 1,
xs: []
}
).xs;
return [result1, result2];
})();
[[1, 2, 3, 4, 5], [1, 2, 3, 4, 5]]
ES6 is a superset of Javascript so the Javascript and ES5 solution is valid. An example of a do-while loop in a generator follows that produces correct output:
// generator with the do while loop
function* getValue(stop) {
var i = 0;
do {
yield ++i;
} while (i % stop != 0);
}
// function to print the value and invoke next
function printVal(g, v) {
if (!v.done) {
console.log(v.value);
setImmediate(printVal, g, g.next());
}
}
(() => {
var gen = getValue(6);
printVal(gen, gen.next());
})();
1
2
3
4
5
6
jq
In jq 1.4, the "recurse" built-in always emits the input value, and so to accomplish the task specified here, we shall define a control structure: "do_while(action; condition)" as follows:
# Perform the action, then check the condition, etc
def do_while( action; condition ):
def w: action | if (condition | not) then empty else ., w end;
w;
The task:
0 | do_while( .+1; . % 6 != 0 )
- Output:
1 2 3 4 5
Julia
Julia has no do-while construct. Here is one of several ways to implement do-while behavior.
julia> i = 0
0
julia> while true
println(i)
i += 1
i % 6 == 0 && break
end
0
1
2
3
4
5
Using a macro that mimics the classic C style do-while.
Notice that the symbol while
cannot be used as it is a keyword, which is why when
is used instead, also the macro definition is wrapped in a @eval
macro invocation since do
is also a keyword, but in Julia macro calls are prefixed by @
so this is only an issue during the macro definition, not when invoked, ie. @do block when condition
).
julia> @eval macro $(:do)(block, when::Symbol, condition)
when ≠ :when && error("@do expected `when` got `$s`")
quote
let
$block
while $condition
$block
end
end
end |> esc
end
@do (macro with 1 method)
julia> i = 0
0
julia> @do begin
@show i
i += 1
end when i % 6 ≠ 0
i = 0
i = 1
i = 2
i = 3
i = 4
i = 5
Here is mostly the same macro, but with the conditional clause used first, which is arguably more readable.
julia> macro do_while(condition, block)
quote
let
$block
while $condition
$block
end
end
end |> esc
end
@do_while (macro with 1 method)
julia> i = 0
0
julia> @do_while i % 6 ≠ 0 begin
@show i
i += 1
end
i = 0
i = 1
i = 2
i = 3
i = 4
i = 5
Kotlin
// version 1.0.6
fun main(args: Array<String>) {
var value = 0
do {
println(++value)
}
while (value % 6 != 0)
}
- Output:
1 2 3 4 5 6
LabVIEW
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.
Lasso
local(x = 0)
while(#x % 6 > 0 || #x == 0) => {^
++#x
'\r' // for formatting
^}
Lambdatalk
{def do_while
{def do_while.r
{lambda {:i}
{if {= {% :i 6} 0}
then :i (end of loop)
else :i {do_while.r {+ :i 1}}}}}
{lambda {:i}
:i {do_while.r {+ :i 1}}}}
-> do_while
{do_while 0}
-> 0 1 2 3 4 5 6 (end of loop)
Lang
Lang does not have a do-while loop. A simple loop like the example below can be used.
$i = 0
loop {
$i += 1
fn.println($i)
if(!($i % 6)) {
con.break
}
}
Lingo
Lingo has no do..while, but here how this behavior can be implemented:
i = 0
repeat while TRUE
i = i+1
put i
if i mod 6 = 0 then exit repeat
end
Lisaac
+ val : INTEGER;
{
val := val + 1;
val.print;
'\n'.print;
val % 6 != 0
}.while_do { };
LiveCode
repeat while n mod 6 is not 0 or n is 0
add 1 to n
put n
end repeat
Logo
make "val 0
do.while [make "val :val + 1 print :val] [notequal? 0 modulo :val 6]
do.until [make "val :val + 1 print :val] [equal? 0 modulo :val 6]
to my.loop :n
make "n :n + 1
print :n
if notequal? 0 modulo :n 6 [my.loop :n]
end
my.loop 0
Lua
Lua doesn't have a do .. while
construct.
i=0
repeat
i=i+1
print(i)
until i%6 == 0
M2000 Interpreter
Module checkit {
x=0
\\ Do or Repeat
Do
x++
print x,
when x mod 6>0
print
// or we can use Until x mod 6 = 0
// and we can use block if we like it
x=0
Do {
x++
print x,
} when x mod 6>0
print
x=0
{
\\ when enter to block the loop flag change to false
x++
if x mod 6<>0 Then loop ' set loop flag of current block to true
\\ when block end check Loop flag and if true execute block again
print x,
}
print
}
Checkit
module Old_Style {
10 REM Loops/Do-while
20 LET I=0
30 LET I=I+1
40 PRINT I
50 IF INT(I/6)*6 <> I THEN 30
60 END
}
Old_Style
// modern style, using high order functions
module generic_iterator {
do_while = lambda (f, p)->{
{
if p(f()) then loop
}
}
funcA=lambda (start_from, do_what) -> {
=lambda i=start_from, do_what ->{
call do_what(i)
=i
i++
}
}
funcPrint=lambda ->{
print number
}
call do_while(funcA(1, funcPrint), lambda->number mod 6 <>0)
}
generic_iterator
- Output:
1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6
Maple
val := 0:
do
val := 1 + val;
print( val );
if irem( val, 6 ) = 0 then
break
end if;
end do:
Mathematica /Wolfram Language
Because everything is an expression in Mathematica, While[body;condition]
tests condition
after body
has been executed at least once.
value = 0;
While[
value++;
Print[value];
Mod[value,6]!=0
]
MATLAB / Octave
a=0;
while (1)
a = a+1;
disp(a);
if (~mod(a,6)) break; end;
end;
Maxima
block([n: 0], do (ldisp(n: n + 1), if mod(n, 6) = 0 then return('done)))$
MAXScript
a = 0
do
(
print a
a += 1
)
while mod a 6 != 0
Metafont
Metafont has no a do-while construct; the same thing can be done using a forever loop and exitif.
a := 0;
forever: show a; a := a + 1; exitif a mod 6 = 0; endfor
end
min
0 (dup 6 mod 0 == over 0 != and) 'pop (puts succ) () linrec
MIPS Assembly
.text
main: li $s0, 0 # start at 0.
li $s1, 6
loop: addi $s0, $s0, 1 # add 1 to $s0
div $s0, $s1 # divide $s0 by $s1. Result is in the multiplication/division registers
mfhi $s3 # copy the remainder from the higher multiplication register to $s3
move $a0, $s0 # variable must be in $a0 to print
li $v0, 1 # 1 must be in $v0 to tell the assembler to print an integer
syscall # print the integer in $a0
bnez $s3, loop # if $s3 is not 0, jump to loop
li $v0, 10
syscall # syscall to end the program
МК-61/52
0 П4 КИП4 ИП4 6 / {x} x=0 02 С/П
Modula-2
MODULE DoWhile;
IMPORT InOut;
VAR
i: INTEGER;
BEGIN
i := 0;
REPEAT
INC(i);
InOut.WriteInt(i, 1);
InOut.WriteLn;
UNTIL i MOD 6 = 0;
END DoWhile.
Modula-3
This is very similar to the Modula-2 code above.
REPEAT
i := i + 1;
IO.Put(Fmt.Int(i));
UNTIL i MOD 6 = 0;
Monicelli
The do-while loop is the only kind of loop available in Monicelli
stuzzica
... # loop body
e brematura anche, se <expr> # exit if <expr> is false
MUMPS
DOWHILELOOP
set val = 0
do {
set val = val + 1
write val,!
} while ((val # 6) '= 0)
quit
- Output:
SAMPLES>do ^DOWHILELOOP 1 2 3 4 5 6
Neko
/**
Loops/Do-while in Neko
Tectonics:
nekoc loops-do-while.neko
neko loops-do-while
*/
var index = 0;
do {
index += 1;
$print(index, "\n");
} while (index % 6) != 0
- Output:
prompt$ nekoc loops-do-while.neko prompt$ neko loops-do-while 1 2 3 4 5 6
Nemerle
mutable x = 0;
do
{
x++;
WriteLine($"$x");
} while (x % 6 != 0)
NetRexx
In NetRexx the do–while construct is implemented via the until expru
conditional clause of the loop
instruction. The expression expru in the until expru
clause is evaluated at the end of the loop, guaranteeing that the loop will be executed at least once.
/* NetRexx */
options replace format comments java crossref savelog symbols nobinary
say
say 'Loops/Do-while'
i_ = 0
loop until i_ // 6 = 0
i_ = i_ + 1
say i_
end
NewLISP
(let ((i 0))
(do-until (= 0 (% i 6))
(println (++ i))))
Nim
Nim does not have a do-while loop. The standard way to simulate it consists in an infinite loop with a break statement:
var val = 0
while true:
inc val
echo val
if val mod 6 == 0: break
Or we can use the statement evaluation to execute code before the check:
var val = 0
while (inc val; echo val; val mod 6 != 0):
discard
It's also easy to write your own doWhile construction (but be aware that the instructions will be duplicated):
template doWhile(a, b: untyped): untyped =
b
while a:
b
var val = 0
doWhile val mod 6 != 0:
inc val
echo val
Nu
mut n = 0
while true {
$n += 1
print $n
if $n mod 6 == 0 {break}
}
Oberon-2
Works with oo2c Version 2
MODULE LoopDoWhile;
IMPORT
Out;
PROCEDURE Do();
VAR
i: INTEGER;
BEGIN
i := 0;
REPEAT
Out.LongInt(i,0);Out.Ln;
INC(i)
UNTIL (i MOD 6 = 0);
END Do;
BEGIN
Do
END LoopDoWhile.
Objeck
i := 0;
do {
i += 1;
i->PrintLine();
}
while (i % 6 <> 0);
OCaml
OCaml doesn't have a do-while loop, so we can just make a local loop:
let rec loop i =
let i = succ i in
Printf.printf "%d\n" i;
if i mod 6 <> 0 then
loop i
in
loop 0
or implementing a generic do-while iterator with higher order function:
let do_while f p =
let rec loop() =
f();
if p() then loop()
in
loop()
(** val do_while : (unit -> 'a) -> (unit -> bool) -> unit *)
let v = ref 0 in
do_while (fun () -> incr v; Printf.printf "%d\n" !v)
(fun () -> !v mod 6 <> 0)
The example above is the an imperative form, below is its functional counterpart:
let do_while f p ~init =
let rec loop v =
let v = f v in
if p v then loop v
in
loop init
do_while (fun v ->
let v = succ v in
Printf.printf "%d\n" v;
(v))
(fun v -> v mod 6 <> 0)
~init:0
Or in a very poor OCaml style, we can use an exception to exit a while loop:
let v = ref 0
exception Exit_loop
try while true do
incr v;
Printf.printf "%d\n" !v;
if not(!v mod 6 <> 0) then
raise Exit_loop;
done
with Exit_loop -> ()
Octave
The do-while can be changed into a do-until, just negating the condition of the while.
val = 0;
do
val++;
disp(val)
until( mod(val, 6) == 0 )
Oforth
0 doWhile: [ 1+ dup . dup 6 rem 0 <> ] drop
OpenEdge/Progress
DEFINE VARIABLE ii AS INTEGER.
DO WHILE ii MODULO 6 <> 0 OR ii = 0:
ii = ii + 1.
MESSAGE ii VIEW-AS ALERT-BOX.
END.
Oz
Normal Oz variables are single-assignment only. So we use a "cell", which is a one-element mutable container.
declare
I = {NewCell 0}
in
for until:@I mod 6 == 0 do
I := @I + 1
{Show @I}
end
PARI/GP
The generic Pari loops (while
, until
) test at the beginning, so just use an infinite loop with a break.
x = 0;
while(1,
print(x++);
if(x % 6 == 0, break)
)
If the loop body is something simple then it might be worked into the loop condition. This is obscure but compact.
x = 0;
while (print(x++) || x % 6, )
The condition in while
and until
is an expression, not a sequence, so ;
for multiple statements cannot be used there.
Pascal
program countto6(output);
var
i: integer;
begin
i := 0;
repeat
i := i + 1;
writeln(i)
until i mod 6 = 0
end.
PascalABC.NET
begin
var a := 0;
repeat
a += 1;
Print(a);
until a mod 6 = 0;
end.
Perl
my $val = 0;
do {
$val++;
print "$val\n";
} while ($val % 6);
do ... until (condition)
is equivalent to do ... while (not condition)
.
my $val = 0;
do {
$val++;
print "$val\n";
} until ($val % 6 == 0);
Phix
integer x = 0 while 1 do x += 1 ?x if mod(x,6)=0 then exit end if end while
Phixmonti
/# Rosetta Code problem: https://rosettacode.org/wiki/Loops/Do-while
by Galileo, 11/2022 #/
include ..\Utilitys.pmt
0
true while
1 +
dup ?
dup 6 mod
endwhile
PHL
var i = 0;
do {
i = i::inc;
printf("%i\n", i);
} while (i%6 != 0);
PHP
$val = 0;
do {
$val++;
print "$val\n";
} while ($val % 6 != 0);
Picat
do while loop
go =>
N = 0,
do
N := N+1,
println(N)
while (N mod 6 != 0).
Recursion
go2 =>
do_while(0).
do_while(N) :-
N1 = N + 1,
println(N1),
N1 mod 6 != 0,
do_while(N1).
Both outputs the same.
- Output:
1 2 3 4 5 6
PicoLisp
Literally:
(let Val 0
(loop
(println (inc 'Val))
(T (=0 (% Val 6))) ) )
Shorter:
(let Val 0
(until (=0 (% (println (inc 'Val)) 6))) )
or:
(for (Val 0 (n0 (% (println (inc 'Val)) 6))))
Pike
int main(){
int value = 0;
do {
value++;
write(value + "\n");
} while (value % 6);
}
PL/0
PL/0 does not have a do .. while
construct. Equivalent using while
:
var i;
begin
i := 0;
i := i + 1;
! i;
while (i / 6) * 6 <> i do
begin
i := i + 1;
! i
end;
end.
- Output:
1 2 3 4 5 6
PL/I
dcl value fixed bin (31) init (0);
do forever;
value = value + 1;
if mod(value, 6) = 0 then
leave;
put list (value);
end;
or shorter:
dcl value fixed bin(31) init(0);
do Until(value=6);
value+=1;
put Skip list(value);
end;
- Output:
1 2 3 4 5 6
Plain English
Plain English has one kind of loop: an infinite loop with (hopefully) a conditional break/exit. So if you want a do-while, put the conditional break/exit at the end of the loop.
To run:
Start up.
Demonstrate do-while.
Wait for the escape key.
Shut down.
To demonstrate do-while:
Bump a counter.
Convert the counter to a string.
Write the string on the console.
If the counter is evenly divisible by 6, exit.
Repeat.
Pop11
lvars val = 0;
while true do
val + 1 -> val;
printf(val, '%p\n');
quitif(val rem 6 = 0);
endwhile;
PowerShell
$n = 0
do {
$n++
$n
} while ($n % 6 -ne 0)
Prolog
% initial condition
do(0):- write(0),nl,do(1).
% control condition
do(V):- 0 is mod(V,6), !, fail.
% loop
do(V) :-
write(V),nl,
Y is V + 1,
do(Y).
wloop :-
do(0).
Python
Python doesn't have a do-while loop.
val = 0
while True:
val +=1
print val
if val % 6 == 0: break
or repeat the body of the loop before a standard while.
val = 1
print val
while val % 6 != 0:
val += 1
print val
Quackery
Quackery's control flow words are mix-and-match. To satisfy this task, we can check for the exit condition at the end of the loop. until
means jump to [
if ToS is false.
0 [ 1+ dup echo cr
dup 6 mod 0 = until ] drop
R
i <- 0
repeat
{
i <- i + 1
print(i)
if(i %% 6 == 0) break
}
Racket
Idiomatic Racket code is functional:
#lang racket
(let loop ([n 0])
(let ([n (add1 n)])
(displayln n)
(unless (zero? (modulo n 6)) (loop n))))
But an imperative version is easy to do too:
#lang racket
(define n 0)
(let loop ()
(set! n (add1 n))
(displayln n)
(unless (zero? (modulo n 6)) (loop)))
Raku
(formerly Perl 6)
my $val = 0;
repeat {
say ++$val;
} while $val % 6;
repeat ... until condition
is equivalent to do ... while not condition
.
my $val = 0;
repeat {
say ++$val;
} until $val %% 6;
(Here we've used %%
, the "divisible-by" operator.)
You can also put the condition before the block, without changing the order of evaluation.
my $val = 0;
repeat while $val % 6 {
say ++$val;
}
REBOL
REBOL [
Title: "Loop/While"
URL: http://rosettacode.org/wiki/Loop/Do_While
]
; REBOL doesn't have a specific 'do/while' construct, but 'until' can
; be used to provide the same effect.
value: 0
until [
value: value + 1
print value
0 = mod value 6
]
- Output:
1 2 3 4 5 6
Red
Red []
i: 0
until [
?? i
i: i + 1
i % 6 = 0 ;; loop , until this is true...
]
- Output:
i: 0 i: 1 i: 2 i: 3 i: 4 i: 5
REXX
In the DO UNTIL construct, the expression is evaluated at the end of the DO loop,
even though it is written at the beginning.
This insures that the DO UNTIL loop will execute at least once (as coded below).
In contrast, a DO WHILE construct, the expression would be evaluated at the beginning of the DO loop, and
may cause the DO WHILE loop to not execute at all.
This necessitates the use of DO UNTIL instead of DO WHILE.
version 1
/*REXX program demonstrates a DO UNTIL construction. */
v=0
do until v//6==0 /*REXX // is the ÷ remainder.*/
v=v+1
say v
end
/*stick a fork in it, we're done.*/
- Output:
1 2 3 4 5 6
version 2
/*REXX program demonstrates a DO UNTIL construction. */
do v=1 until v//6==0 /*REXX // is the ÷ remainder.*/
say v
end
/*stick a fork in it, we're done.*/
output is the same as the 1st version.
Ring
n = 0
While True
n++ See n + nl
if n % 6 = 0 exit ok
end
RPL
To ensure at least one loop, DO
..UNTIL
..END
must be used rather than WHILE
..REPEAT
..END
. To actually print (on paper) instead of pushing in the stack successive results, the DUP
instruction inside the loop shall be replaced by PR1
≪ 0 DO 1 + DUP UNTIL DUP 6 MOD 0 == END DROP ≫
Ruby
The while statement modifier normally checks the condition before entering the loop. But if the while statement modifier is on a begin ... end statement, then it loops at least once. Same with the until statement modifier.
while | until |
---|---|
val = 0
begin
val += 1
puts val
end while val % 6 != 0 |
val = 0
begin
val += 1
puts val
end until val % 6 == 0 |
During November 2005, Yukihiro Matsumoto, the creator of Ruby, regretted this loop feature and suggested using Kernel#loop.
break unless | break if |
---|---|
val = 0
loop do
val += 1
puts val
break unless val %6 != 0
end |
val = 0
loop do
val += 1
puts val
break if val %6 == 0
end |
All four of these examples print the numbers 1, 2, 3, 4, 5, 6.
Rust
Rust does not have a do...while loop. Instead, the keyword loop is used with a termination condition.
let mut x = 0;
loop {
x += 1;
println!("{}", x);
if x % 6 == 0 { break; }
}
Salmon
variable x := 0;
do
{
++x;
x!
}
while (x % 6 != 0);
SAS
/* using DO UNTIL so that the loop executes at least once */
data _null_;
n=0;
do until(mod(n,6)=0);
n+1;
put n;
end;
run;
Sather
class MAIN is
main is
val ::= 0;
loop
val := val + 1;
#OUT + val + "\n";
while!(val % 6 /= 0)
end;
end;
end;
S-BASIC
S-BASIC's REPEAT..UNTIL control structure is the equivalent of a DO..WHILE statement with the terminating test inverted.
rem - return n mod m
function mod(n, m = integer) = integer
end = n - (n / m) * m
var i = integer
i = 0
repeat
begin
i = i + 1
print i;
end
until mod(i, 6) = 0
end
- Output:
1 2 3 4 5 6
Scala
Imperative
{
var (x, l) = (0, List[Int]())
do {
x += 1
l :+= x // A new copy of this list with List(x) appended.
} while (x % 6 != 0)
l
}.foreach(println(_))
Tail recursive
def loop(iter: Int, cond: (Int) => Boolean, accu: List[Int]): List[Int] = {
val succ = iter + 1
val temp = accu :+ succ
if (cond(succ)) loop(succ, cond, temp) else temp
}
println(loop(0, (_ % 6 != 0), Nil))
Stream
def loop(i: Int, cond: (Int) => Boolean): Stream[Int] = {
val succ = i + 1;
succ #:: (if (cond(succ)) loop(succ, cond) else Stream.empty)
}
loop(0, (_ % 6 != 0)).foreach(println(_))
Scheme
(let loop ((i 1))
(display i)
(if (positive? (modulo i 6))
(loop (+ i 1))))
Scilab
v=0
while %T
v=v+1
printf("%2d ",v)
if modulo(v,6)==0 then break; end
end
printf("\n")
- Output:
1 2 3 4 5 6
Seed7
$ include "seed7_05.s7i";
const proc: main is func
local
var integer: number is 0;
begin
repeat
incr(number);
writeln(number)
until number rem 6 = 0
end func;
Sidef
var value = 0;
do {
say ++value;
} while (value % 6);
Slate
[| val |
val: 0.
[val: val + 1.
print: val.
val \\ 6 ~= 0] whileTrue
] do.
Smalltalk
|val|
val := 0.
[
val := val + 1.
val displayNl.
] doWhile: [ (val rem: 6) ~= 0 ]
|val|
val := 0.
[
val := val + 1.
val displayNl.
] doUntil: [ (val rem: 6) == 0 ]
To simulate the do-while construct, we can use the whileTrue: method of a block with a void while block.
|val|
val := 0.
[
val := val + 1.
val displayNl.
(val rem: 6) ~= 0
] whileTrue: [ ]
Or send the loop block a whileTrue message (without argument).
|val|
val := 0.
[
val := val + 1.
val displayNl.
(val rem: 6) ~= 0
] whileTrue
Corresponding false-checking messages are whileFalse: and whileFalse (without argument)
Sparkling
var i = 0;
do {
print(++i);
} while (i % 6 != 0);
Spin
con
_clkmode = xtal1 + pll16x
_clkfreq = 80_000_000
obj
ser : "FullDuplexSerial.spin"
pub main | n
ser.start(31, 30, 0, 115200)
n := 0
repeat
n += 1
ser.dec(n)
ser.tx(32)
while n // 6
waitcnt(_clkfreq + cnt)
ser.stop
cogstop(0)
- Output:
1 2 3 4 5 6
SPL
n = 0
>
n += 1
#.output(n)
< n%6
- Output:
1 2 3 4 5 6
Stata
Stata macro language has no do/while loop, but it's possible to achieve this with a while loop.
Use a flag to force the first loop. It's changed in the loop so that it will have no effect after the first loop.
local n 0
local q 1
while `q' | mod(`n',6) {
local q 0
di `++n'
}
Use an infinite while loop and do the test with an if' at the end of the loop.
local n 0
while 1 {
di `++n'
if mod(`n',6)==0 continue, break
}
Mata
Mata has a do/while loop:
mata
n=0
do {
printf("%f\n",++n)
} while (mod(n,6))
end
Suneido
val = 0
do
{
Print(++val)
} while (val % 6 isnt 0)
- Output:
1 2 3 4 5 6
Swift
var val = 0
repeat {
val += 1
print(val)
} while val % 6 != 0
var val = 0
repeat {
val++
print(val)
} while val % 6 != 0
var val = 0
do {
val++
println(val)
} while val % 6 != 0
Tailspin
In Tailspin you can loop by sending a value back to the matchers (by "-> #"). Depending on how you set that up, you create different loops.
templates doWhile
0 -> #
<> def val: $ + 1;
$val -> !OUT::write
$val -> \(<?($ mod 6 <~=0>)> $!\) -> #
end doWhile
v0.5 (also replacing the print with an emit)
doWhile source
0 -> # !
otherwise val is $ + 1;
$val !
$val -> if <|?($ mod 6 matches <~|=0>)> -> # !
end doWhile
$doWhile !
TAV
The language intentionally has no 'do-while', because it is seldomly useful; only a loop with optional while condition. For the effect of a 'while-do', an endless loop is terminated conditionally.
x =: 0
?* \ loop forever
x =+ 1 \ increment x
print x
? x %% 6 = 0 \ until
?> \ break
- Output:
1 2 3 4 5 6
Tcl
Tcl does not have a built-in do...while
construct. This example demonstrates the ease of creating new looping contructs in plain Tcl. do
procedure taken from Tcler's wiki
proc do {body keyword expression} {
if {$keyword eq "while"} {
set expression "!($expression)"
} elseif {$keyword ne "until"} {
return -code error "unknown keyword \"$keyword\": must be until or while"
}
set condition [list expr $expression]
while 1 {
uplevel 1 $body
if {[uplevel 1 $condition]} {
break
}
}
return
}
set i 0
do {puts [incr i]} while {$i % 6 != 0}
package require control
set i 0; control::do {puts [incr i]} while {$i % 6 != 0}
set i 0; control::do {puts [incr i]} until {$i % 6 == 0}
Mind you, it is also normal to write this task using a normal while
as:
set i 0
while true {
puts [incr i]
if {$i % 6 == 0} break
}
TUSCRIPT
$$ MODE TUSCRIPT
var=0
LOOP
var=var+1, rest=var%6
PRINT var
IF (rest==0) EXIT
ENDLOOP
- Output:
1 2 3 4 5 6
UNIX Shell
val=0
while true; do
echo $((++val))
[ $((val%6)) -eq 0 ] && break
done
val=0
while true; do
val=`expr $val + 1`
echo $val
expr $val % 6 = 0 >/dev/null && break
done
for ((val=1;;val++)) {
print $val
(( val % 6 )) || break
}
Vala
int a = 0;
do {
a++;
print(a.to_string() + "\n");
}
while ( a % 6 != 0);
Vedit macro language
#1 = 0
do {
#1++
Num_Type(#1)
} while (#1 % 6 != 0);
Verbexx
// Basic @LOOP until: verb
@LOOP init:{@VAR n = 0} until:(n % 6 == 0)
{
n++;
@SAY n;
};
Verilog
module main;
integer i;
initial begin
i = 1;
$write(i);
while(i % 6 != 0) begin
i = i + 1;
$write(i);
end
$finish ;
end
endmodule
V (Vlang)
There is no explicit do-while in Vlang, but it can be simulated with a range-based for loop and the break statement.
fn main() {
mut value := 0
for {
value++
println(value)
if value%6 != 0 {
break
}
}
}
- Output:
1 2 3 4 5 6
It can also be simulated without using a break statement as follows:
fn main() {
mut value := 0
for ok := true; ok; ok = value%6 != 0 {
value++
println(value)
}
}
- Output:
Same as before.
fn main() { // do-while loop 1 mut n1 := 2 for n1 < 6 { n1 *= 2 } println(n1) // prt 8 // do-while loop 2 mut n2 := 2 for ok := true; ok; ok = n2%8 != 0 { n2 *= 2 } println(n2) // prt 8 // do-while loop 3 mut n3 := 2 for { n3 *= 2 if n3 >= 6 { break } } println(n3) // prt 8 }
Wren
Wren doesn't have a do/while loop as such but we can simulate it using an infinite loop with a final conditional break.
var v = 0
while (true) {
v = v + 1
System.print(v)
if (v%6 == 0) break
}
- Output:
1 2 3 4 5 6
It can also be simulated without using a break statement as follows:
var value = 0
var ok = true
while (ok) {
value = value + 1
System.print(value)
ok = value%6 != 0
}
- Output:
Same as before.
X86 Assembly
extern _printf
section .data
output db 0,0
section .text
global _main
_main:
mov bl, 0
looping:
add bl, 0x31 ;0x30 to 0x39 is 0 to 9 in ASCII
mov [output], bl
sub bl, 0x30
push output
call _printf
add esp, 4
xor eax, eax
xor edx, edx
mov al, bl
mov ecx, 6
div ecx ; remainder is saved in edx
cmp edx, 0
jne looping ; if n & 6 != 0 do looping again
xor eax, eax
ret
XPL0
code CrLf=9, IntOut=11;
int V;
[V:= 0;
repeat V:= V+1;
IntOut(0, V); CrLf(0);
until rem(V/6) = 0;
]
Yorick
val = 0;
do {
val++;
write, val;
} while(val % 6 != 0);
zkl
val := 0;
do {
val+=1;
val.print(" ");
} while(val % 6 != 0);
- Output:
1 2 3 4 5 6
Zig
const std = @import("std");
pub fn main() !void {
var a: u8 = 0;
// no do-while in syntax, trust the optimizer to do
// correct Loop inversion https://en.wikipedia.org/wiki/Loop_inversion
// If the variable `alive` is independent to other variables and not in
// diverging control flow, then the optimization is possible in general.
var alive = true;
while (alive == true or a % 6 != 0) {
alive = false;
a += 1;
try std.io.getStdOut().writer().print("{d}\n", .{a});
}
}
- Programming Tasks
- Iteration
- Conditional loops
- Simple
- 11l
- 360 Assembly
- 6502 Assembly
- AArch64 Assembly
- Action!
- ActionScript
- Ada
- Agena
- Aime
- ALGOL 60
- ALGOL 68
- ALGOL W
- AmigaE
- ARM Assembly
- AppleScript
- Arturo
- Asymptote
- AutoHotkey
- AWK
- Axe
- BASIC
- Applesoft BASIC
- ASIC
- BaCon
- BASIC256
- BBC BASIC
- Chipmunk Basic
- Commodore BASIC
- FreeBASIC
- Gambas
- GW-BASIC
- IS-BASIC
- Liberty BASIC
- Microsoft Small Basic
- Minimal BASIC
- MSX Basic
- NS-HUBASIC
- PureBasic
- QB64
- QBasic
- Quite BASIC
- Run BASIC
- Sinclair ZX81 BASIC
- SmallBASIC
- Tiny BASIC
- True BASIC
- VBA
- Visual Basic .NET
- XBasic
- Yabasic
- Bc
- Befunge
- C
- C sharp
- C++
- C3
- Chapel
- ChucK
- Clipper
- Clojure
- COBOL
- Coco
- CoffeeScript
- ColdFusion
- Common Lisp
- D
- Dart
- Dc
- Delphi
- Draco
- Dragon
- DuckDB
- DUP
- DWScript
- Dyalect
- E
- EasyLang
- Ela
- Elixir
- Emacs Lisp
- Erlang
- ERRE
- Euphoria
- F Sharp
- Factor
- Fantom
- Forth
- Fortran
- Fortress
- Frink
- FutureBasic
- GAP
- GML
- Go
- Groovy
- Harbour
- Haskell
- Haxe
- HolyC
- Icon
- Unicon
- J
- Java
- JavaScript
- Jq
- Julia
- Kotlin
- LabVIEW
- Lasso
- Lambdatalk
- Lang
- Lingo
- Lisaac
- LiveCode
- Logo
- Lua
- M2000 Interpreter
- Maple
- Mathematica
- Wolfram Language
- MATLAB
- Octave
- Maxima
- MAXScript
- Metafont
- Min
- MIPS Assembly
- МК-61/52
- Modula-2
- Modula-3
- Monicelli
- MUMPS
- Neko
- Nemerle
- NetRexx
- NewLISP
- Nim
- Nu
- Oberon-2
- Objeck
- OCaml
- Oforth
- OpenEdge/Progress
- Oz
- PARI/GP
- Pascal
- PascalABC.NET
- Perl
- Phix
- Phixmonti
- PHL
- PHP
- Picat
- PicoLisp
- Pike
- PL/0
- PL/I
- Plain English
- Pop11
- PowerShell
- Prolog
- Python
- Quackery
- R
- Racket
- Raku
- REBOL
- Red
- REXX
- Ring
- RPL
- Ruby
- Rust
- Salmon
- SAS
- Sather
- S-BASIC
- Scala
- Scheme
- Scilab
- Seed7
- Sidef
- Slate
- Smalltalk
- Sparkling
- Spin
- SPL
- Stata
- Suneido
- Swift
- Tailspin
- TAV
- Tcl
- Tcllib
- TUSCRIPT
- UNIX Shell
- Vala
- Vedit macro language
- Verbexx
- Verilog
- V (Vlang)
- Wren
- X86 Assembly
- XPL0
- Yorick
- Zkl
- Zig
- GUISS/Omit
- Pages with too many expensive parser function calls