PHP While Loop

PHP While, Do-While Loop

PHP While Loop We have already discussed the PHP For Loop. Now we are discussing about another loop.

In PHP, we have the following looping statements:

PHP While Loop

The while loop executes a block of code as long as the specified condition is true.

Syntax

while (condition) {
    block of code;
}

Example

<?php
$i = 0;
while ($i < 5)
{
	echo "<br> value of i is " . $i;
	$i++;
}
?>

Output

value of i is 0
value of i is 1
value of i is 2
value of i is 3
value of i is 4

At the end of each execution, while condition is checked again. If the condition has a true value, the block of code will be executed again. If condition has a false value, the loop was broken.

Do While loop

The do while is same as the while loop but main difference is the block of code will be executed at least once before the condition is checked for a true or false value then repeats the loop as long as the specified condition is true.

Syntax

do {
    block of code;
} while (condition);

Example

<?php
$i = 0;
do
{
 echo “<br> value of i is” . $i;
 $i++;
} while ($i < 5);
?>

Output

value of i is 0
value of i is 1
value of i is 2
value of i is 3
value of i is 4

Infinite While loop

It is an infinite loop which will execute the block of code till a break statement is applied explicitly. Therefore while(1), while(true) or while(-130)  all will give infinite loop only.

Use of Infinite while loop is in the Client-Server program. In the program, the server runs in an infinite while loop to receive the packets sent form the clients.

Syntax

while (1) or while (true) or while (any non-zero integer) {
    block of code;
}

Example

<?php
while (1)
{
	echo "<br> developer helps";
}
?>

Output

developer helps
developer helps
developer helps
developer helps
developer helps
developer helps
developer helps
developer helps...... infinity times

While (0) or While (false) loop

Condition will always be false in this case so block of code will never get executed.

Syntax

while (0) or while (false){
    block of code;
}

Example

<?php
while (0)
{
	echo "<br> developer helps";
}
echo "while loop not execute";
?>

Output

while loop not execute

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