Loops/Do-while
From Rosetta Code
You are encouraged to solve this task according to the task description, using any language you may know.
[edit] 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
[edit] ActionScript
var val:int = 0;
do
{
trace(++val);
} while (val % 6);
[edit] 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;
[edit] ALGOL 68
FOR value WHILE
print(value);
# WHILE # value MOD 6 /= 0 DO
SKIP
OD
[edit] AmigaE
PROC main()
DEF i = 0
REPEAT
i := i + 1
WriteF('\d\n', i)
UNTIL Mod(i, 6) = 0
ENDPROC
[edit] AutoHotkey
While mod(A_Index, 6) ;comment:everything but 0 is considered true
output = %output%`n%A_Index%
MsgBox % output
[edit] AWK
BEGIN {
val = 0
do {
val++
print val
} while( val % 6 != 0)
}
[edit] BASIC
Works with: QuickBasic version 4.5
a = 0
DO
a = a + 1
PRINT a
LOOP WHILE a MOD 6 <> 0
[edit] Befunge
0>1+:.v
|%6: <
@
[edit] C
int val = 0;
do{
val++;
printf("%d\n",val);
}while(val % 6 != 0);
[edit] C++
int val = 0;
do{
val++;
cout << val << endl;
}while(val % 6 != 0);
[edit] C#
int a = 0;
do
{
Console.WriteLine(a);
a += 1;
} while (a % 6 != 0);
[edit] ColdFusion
<cfscript>
value = 0;
do
{
value += 1;
writeOutput( value );
} while( value % 6 != 0 );
</cfscript>
[edit] Common Lisp
(setq val 0)
(loop do
(incf val)
(print val)
while (/= 0 (mod val 6)))
[edit] D
int val = 0;
do{
val++;
writefln(val);
}while(val % 6 != 0);
[edit] 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
})
[edit] Erlang
do() ->
io:format("0~n"),
do(1).
do(N) when N rem 6 =:= 0 ->
io:format("~w~n", [N]);
do(N) ->
io:format("~w~n", [N]),
do(N+1).
[edit] Factor
0 [ dup 6 mod 0 = not ] [ [ . ] [ 1 + ] bi ] do while drop
[edit] Forth
: do-until
0
begin 1+
dup .
dup 6 mod 0=
until
drop ;
[edit] Fortran
Works with: Fortran version 90 and later
INTEGER :: i = 0
DO
i = i + 1
WRITE(*, *) i
IF (MOD(i, 6) == 0) EXIT
END DO
[edit] 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
[edit] 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.)
[edit] Icon
procedure main()
i := 0
repeat {
write(i +:= 1)
if i % 6 = 0 then break
}
end
[edit] Unicon
The Icon solution works in Unicon.
[edit] 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
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.
[edit] Java
int val = 0;
do{
val++;
System.out.println(val);
}while(val % 6 != 0);
[edit] JavaScript
var val = 0;
do {
print(++val);
} while (val % 6);
[edit] Lua
Lua doesn't have a do .. while construct.
i=0
repeat
i=i+1
print(i)
until i%6 == 0
[edit] Lisaac
+ val : INTEGER;
{
val := val + 1;
val.print;
'\n'.print;
val % 6 != 0
}.while_do { };
[edit] 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
[edit] Mathematica
value = 5;
NestWhile[
# + 1 &
,
value
, (Print[#]; Mod[#, 6] != 0) &
];
gives back:
5
6
If the starting value is 6, only 6 is returned.
[edit] MAXScript
a = 0
do
(
print a
a += 1
)
while mod a 6 != 0
[edit] 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
[edit] Objeck
i := 0;
do {
i->PrintLine();
i += 1;
}
while (i % 6 <> 0);
[edit] 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 -> ()
[edit] 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 )
[edit] 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
[edit] Pascal
program countto6(output);
var
i: integer;
begin
i := 0;
repeat
i := i + 1;
writeln(i)
until i mod 6 = 0
end.
[edit] 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);
[edit] Perl 6
Works with: Rakudo Star version 2010.08
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;
}
[edit] PHP
$val = 0;
do {
$val++;
print "$val\n";
} while ($val % 6 != 0);
[edit] 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))))
[edit] Pike
int main(){
int value = 0;
do {
value++;
write(value + "\n");
} while (value % 6);
}
[edit] PL/I
value = 0;
do value = 0, value+1 while (mod(value,6) ^= 0);
put list (value);
end;
[edit] Pop11
lvars val = 0;
while true do
val + 1 -> val;
printf(val, '%p\n');
quitif(val rem 6 = 0);
endwhile;
[edit] PowerShell
$n = 0
do {
$n++
$n
} while ($n % 6 -ne 0)
[edit] 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).
[edit] PureBasic
Works with: PureBasic version 4.41
x=0
Repeat
x+1
Debug x
Until x%6=0
[edit] 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
[edit] R
i <- 0
repeat
{
i <- i + 1
print(i)
if(i %% 6 == 0) break
}
[edit] REBOL
rebol [
Title: "Loop/While"
Author: oofoe
Date: 2009-12-19
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
[edit] REXX
In the do until construct, the expression is evaluated at the end, even though it is written at the beginning.
v = 0
do until v//6 = 0
v = v + 1
say v
end
[edit] Ruby
val = 0
begin
val += 1
puts val
end while val % 6 != 0
begin ... end until condition is equivalent to begin ... end while not condition.
val = 0
begin
val += 1
puts val
end until val % 6 == 0
[edit] Sather
Translation of: C
class MAIN is
main is
val ::= 0;
loop
val := val + 1;
#OUT + val + "\n";
while!(val % 6 /= 0)
end;
end;
end;
[edit] Scheme
(let loop ((i 1))
(display i)
(if (positive? (modulo i 6))
(loop (+ i 1))))
[edit] 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;
[edit] Slate
[| val |
val: 0.
[val: val + 1.
print: val.
val \\ 6 ~= 0] whileTrue
] do.
[edit] Smalltalk
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: [ ]
[edit] Suneido
val = 0
do
{
Print(++val)
} while (val % 6 isnt 0)
Output:
1
2
3
4
5
6
[edit] 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}
The control package of Library: tcllib has this:
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
}
[edit] Vedit macro language
#1 = 0
do {
#1++
Num_Type(#1)
} while (#1 % 6 != 0);
[edit] Visual Basic .NET
Dim i = 0
Do
i += 1
Console.WriteLine(i)
Loop Until i Mod 6 = 0
