Do While Loop

Do-while is a loop that executes one or more times

Syntax

do { // code to execute one or more times } while (condition);

False Condition Example

<?php $num = 15; do { echo $num . " "; $num++; } while ($num < 10);

Output:

15

The condition is false but num is printed.

The loop body executes before the condition is checked.

Basically for conditions that are always false, the loop executes once unlike the while cycles which won't execute.

Basic Example

<?php $num = 0; do { echo $num . " "; $num++; } while ($num < 10);

Output:

0 1 2 3 4 5 6 7 8 9

The loop executes 10 times (for num from 0 to 9).

The cycle ends when num reaches value of 10.

Infinite loop

Infinite Loop has a condition that's always true.

It can be created due to development mistake or used in advanced algorithm.

Here are examples:

<?php $num = 0; do { echo $num . " "; } while ($num < 10);

Output:

0 0 0 0 0 0 0 0 0 ...

Since num is 0 and never gets modified, the loop repeats infinitely.

<?php do { echo "1 "; } while (true); 1 1 1 1 1 1 1 1 1 ...

while(true) is a way to specify endless loop.