PHP - Break Statement

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The break statement along with the continue statement in PHP are known as "loop control statements". Any type of loop (for, while or do-while) in PHP is designed to run for a certain number of iterations, as per the test condition used. The break statement inside the looping block takes the program flow outside the block, abandoning the rest of iterations that may be remaining.

The break statement is normally used conditionally. Otherwise, the loop will terminate without completing the first iteration itself.

Syntax of the Break Statement

The syntax of break statement is as follows −

while(expr){
   if (condition){
      break;
   }
}

Flowchart for Break Statement

The following flowchart explains how the break statement works −

The loop starts by checking a condition. If the condition is false, the loop ends. If the condition is satisfied, the program will move to the next phase. If the condition is true, the program runs some code within the loop.

If a break statement is present, the loop will be ended immediately. If there is no break, the loop resumes. This is a common programming method for ending a loop early when a predefined condition is met.

Using Break in a While Loop

The following PHP code is a simple example of using break in a loop. The while loop is expected to perform ten iterations. However, a break statement inside the loop terminates it when the counter exceeds 3.

<?php
   $i = 1;

   while ($i<=10){
      echo "Iteration No. $i \n";
      if ($i>=3){
         break;
      }
      $i++;
   }
?>

Output

It will generate the following result −

Iteration No. 1
Iteration No. 2
Iteration No. 3

An optional numeric argument can be given in front of break keyword. It is especially useful in nested looping constructs. It tells how many nested enclosing structures are to be broken out of. The default value is 1, only the immediate enclosing structure is broken out of.

Using Break with Nested Loops

The following example has three nested loops: a for loop inside which there is a while loop which in turn contains a do-while loop.

The innermost loop executes the break. The number "2" in front of it takes the control out of the current scope into the for loop instead of the immediate while loop.

<?php
   for ($x=1; $x<=3; $x++){
      $y=1;
      while ($y<=3){
         $z=1;
         do {
            echo "x:$x y:$y z:$z \n";
            if ($z==2){
               break 2;
            }
            $z++;
         }
         while ($z<=3);
         $z=1;
         $y++;
      }
   }
?>

Output

It will produce the below output −

x:1 y:1 z:1
x:1 y:1 z:2
x:2 y:1 z:1
x:2 y:1 z:2
x:3 y:1 z:1
x:3 y:1 z:2

Note that each time the value of "z" becomes 2, the program breaks out of the "y" loop. Hence, the value of "y" is always 1.

Using Break in a For Loop

In this example the loop runs from 1 to 10 but the break statement stops execution when $i reaches 5.

<?php
   for ($i = 1; $i <= 10; $i++){
      echo "Iteration No. $i \n";
      if ($i == 5){
         break;
      }
   }
?>

Output

It will generate the following output −

Iteration No. 1  
Iteration No. 2  
Iteration No. 3  
Iteration No. 4  
Iteration No. 5 

Using Break in a Do-While Loop

In the following example, we will use a do-while loop with break statement. So the condition is checked after executing the loop body at least once. The loop executes at least once. When $num == 3, the break statement executes and stop the loop.

<?php
   $num = 1;

   do {
      echo "Value: $num \n";
      if ($num == 3){
         break;
      }
      $num++;
   } while ($num <= 5);
?> 

Output

Following is the output of the above code −

Value: 1  
Value: 2  
Value: 3