PHP Control Statements 1

PHP While Loop

PHP while loop can be used to traverse set of code like for loop.

It should be used if number of iteration is not known.

Syntax

1.            while(condition){  

2.            //code to be executed  

3.            }  

Alternative Syntax

1.            while(condition):  

2.            //code to be executed  

3.              

4.            endwhile;  

PHP While Loop Flowchart

PHP While Loop Example

1.            <?php  

2.            $n=1;  

3.            while($n<=10){  

4.            echo "$n<br/>";  

5.            $n++;  

6.            }  

7.            ?>  

Output:

1

2

3

4

5

6

7

8

9

10

Alternative Example

1.            <?php  

2.            $n=1;  

3.            while($n<=10):  

4.            echo "$n<br/>";  

5.            $n++;  

6.            endwhile;  

7.            ?>  

Output:

1

2

3

4

5

6

7

8

9

10

PHP Nested While Loop

We can use while loop inside another while loop in PHP, it is known as nested while loop.

In case of inner or nested while loop, nested while loop is executed fully for one outer while loop. If outer while loop is to be executed for 3 times and nested while loop for 3 times, nested while loop will be executed 9 times (3 times for 1st outer loop, 3 times for 2nd outer loop and 3 times for 3rd outer loop).

Example

1.            <?php  

2.            $i=1;  

3.            while($i<=3){  

4.            $j=1;  

5.            while($j<=3){  

6.            echo "$i   $j<br/>";  

7.            $j++;  

8.            }  

9.            $i++;  

10.         }  

11.         ?>  

Output:

1 1

1 2

1 3

2 1

2 2

2 3

3 1

3 2

3 3

PHP do while loop

PHP do while loop can be used to traverse set of code like php while loop. The PHP do-while loop is guaranteed to run at least once.

It executes the code at least one time always because condition is checked after executing the code.

Syntax

1.            do{  

2.            //code to be executed  

3.            }while(condition);  

Flowchart

Example

1.            <?php  

2.            $n=1;  

3.            do{  

4.            echo "$n<br/>";  

5.            $n++;  

6.            }while($n<=10);  

7.            ?>  

Output:

1

2

3

4

5

6

7

8

9

10

PHP Break

PHP break statement breaks the execution of current for, while, do-while, switch and for-each loop. If you use break inside inner loop, it breaks the execution of inner loop only.

Syntax

1.            jump statement;  

2.            break;  

Flowchart

PHP Break: inside loop

Let's see a simple example to break the execution of for loop if value of i is equal to 5.

1.            <?php  

2.            for($i=1;$i<=10;$i++){  

3.            echo "$i <br/>";  

4.            if($i==5){  

5.            break;  

6.            }  

7.            }  

8.            ?>  

Output:

1

2

3

4

5

PHP Break: inside inner loop

The PHP break statement breaks the execution of inner loop only.

1.            <?php  

2.            for($i=1;$i<=3;$i++){  

3.             for($j=1;$j<=3;$j++){  

4.              echo "$i   $j<br/>";  

5.              if($i==2 && $j==2){  

6.               break;  

7.              }  

8.             }  

9.            }  

10.         ?>  

Output:

1 1

1 2

1 3

2 1

2 2

3 1

3 2

3 3

PHP Break: inside switch statement

The PHP break statement breaks the flow of switch case also.

1.            <?php      

2.            $num=200;      

3.            switch($num){      

4.            case 100:      

5.            echo("number is equals to 100");      

6.            break;      

7.            case 200:      

8.            echo("number is equal to 200");      

9.            break;      

10.         case 50:      

11.         echo("number is equal to 300");      

12.         break;      

13.         default:      

14.         echo("number is not equal to 100, 200 or 500");      

15.         }     

16.         ?>      

Output:

number is equal to 200