Posts Tagged ‘php do while loop’

PHP While Loops

Loops execute a block of code a specified number of times, or while a specified condition is true.

PHP Loops

Often when you write code, you want the same block of code to run over and over again in a row. Instead of adding several almost equal lines in a script we can use loops to perform a task like this.

In PHP, we have the following looping statements:

  • while – loops through a block of code while a specified condition is true
  • do…while – loops through a block of code once, and then repeats the loop as long as a specified condition is true
  • for – loops through a block of code a specified number of times
  • foreach – loops through a block of code for each element in an array

 

The while Loop

The while loop executes a block of code while a condition is true. If the test expression is true then the code block will be executed. After the code has executed the test expression will again be evaluated and the loop will continue until the test expression is found to be false.

Syntax

 while (condition)
   {
   code to be executed;
   }

Example

The example below first sets a variable i to 1 ($i=1;).

Then, the while loop will continue to run as long as i is less than, or equal to 5. i will increase by 1 each time the loop runs:

<html>
<body>

<?php
$i=1;
while($i<=5)
  {
  echo "The number is " . $i . "<br>";
  $i++;
  }
?>

</body>
</html>

Output:

The number is 1
The number is 2
The number is 3
The number is 4
The number is 5

 

The do…while Statement

The do…while statement will always execute the block of code once, it will then check the condition, and repeat the loop while the condition is true.

Syntax

do
  {
  code to be executed;
 
}
while (condition);

Example

The example below first sets a variable i to 1 ($i=1;).

Then, it starts the do…while loop. The loop will increment the variable i with 1, and then write some output. Then the condition is checked (is i less than, or equal to 5), and the loop will continue to run as long as i is less than, or equal to 5:

<html>
<body>

<?php
$i=1;
do
  {
  $i++;
  echo "The number is " . $i . "<br>";
  }
while ($i<=5);
?>

</body>
</html>

Output:

The number is 2
The number is 3
The number is 4
The number is 5
The number is 6

 

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