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Perform an action multiple times based on a boolean condition, checked before the first action (WHILE .. DO)

Starting with a variable x=1, Print the sequence "1,2,4,8,16,32,64,128," by doubling x and checking that x is less than 150.

php

$x = 1;
while($x < 150) {
echo "$x,";
$x *= 2;
}

$x = 0;
$c = pow(2, $x);
while($c < 150) {
echo "$c,";
$c = pow(2, $x++);
}

erlang

X = 1, print_while_X_less_150(X).

Pred = fun (X) -> X < 150 end,
Action = fun (X) -> io:format("~B,", [X]), X * 2 end,
X = 1,

while_do(Pred, Action, X).

cpp

int x = 1;

while (x < 150) { x *= 2; Console::Write("{0},", x); }
Console::WriteLine();

for (int x = 1; x < 150; x *= 2) { std::cout << x << ","; }
std::cout << std::endl;

Perform an action multiple times based on a boolean condition, checked after the first action (DO .. WHILE)

Simulate rolling a die until you get a six. Produce random numbers, printing them until a six is rolled. An example output might be "4,2,1,2,6"

php

do {
$rand = rand(1,6);
echo $rand;
if ($rand != 6) echo ", ";
} while ($rand != 6);

erlang

Pred = fun (DiceRoll) -> DiceRoll =/= 6 end,
Action = fun (DiceRoll) -> io:format("~B,", [DiceRoll]), dice_roll() end,

do_while(Pred, Action, dice_roll()).

-module(dice).
-export([start/0]).

start() ->
roll(dice_roll()).

roll(6) ->
io:format("6~n", []);
roll(N) ->
io:format("~B,", [N]),
roll(dice_roll()).

dice_roll() -> random:uniform(6).

cpp

Random^ rnd = gcnew Random;

int dice = rnd->Next(1, 7); Console::Write("{0}", dice);
do { Console::Write(",{0}", (dice = rnd->Next(1, 7))); } while (dice != 6);
Console::WriteLine();

Perform an action a fixed number of times (FOR)

Display the string "Hello" five times like "HelloHelloHelloHelloHello"

php

for($i = 0; $i < 5; $i++) {
echo "Hello";
}

erlang

dotimes(5, fun () -> io:format("Hello") end).

lists:foreach(fun (_) -> io:format("Hello") end, lists:seq(1, 5)).

cpp

for(int i = 0; i < 5; ++i) Console::Write("Hello");

for(int i = 5; i > 0; --i) Console::Write("Hello");

dotimes(5, hello);

fill_n(ostream_iterator<string>(cout), 5, "Hello");

Perform an action a fixed number of times with a counter

Display the string "10 .. 9 .. 8 .. 7 .. 6 .. 5 .. 4 .. 3 .. 2 .. 1 .. Liftoff!"

php

for($i = 10; $i > 0; $i--) {
echo $i." .. ";
}
echo "Liftoff!";

erlang

fromto(10, 1, -1, fun (X) -> io:format("~B .. ", [X]) end), io:format("Liftoff!~n").

lists:foreach(fun (X) -> io:format("~B .. ", [X]) end, lists:seq(10, 1, -1)), io:format("Liftoff!~n").

cpp

for(int i = 10; i != 0; --i) Console::Write("{0} .. ", i);
Console::WriteLine("Liftoff!");