Perl do while Loop

Unlike for and while loop, the do while loop checks its condition at the bottom of the loop. So do while loop will execute at least once.

Syntax

The syntax of Perl language do-while loop is given below:

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

Example

This is the simple program of Perl do while loop where we are printing the table of 1.

snippet

$i = 1;
# do...while loop execution
do{
   printf "$i\n";
   $i++;
}while( $i <= 10 );

Output

1 2 3 4 5 6 7 8 9 10

Nested do while Loop

A nested do while loop is the one in which a do while loop is nested inside another do while loop.

It is executed completely for both inner and outer loops.

Example

snippet

$i = 1;
# do...while loop execution
do{
   $j = 1;
   do{
   printf "$i $j\n";
   $j++;
}while( $j <= 3 );
$i++;
}while( $i <= 3 );

Output

1 1 1 2 1 3 2 1 2 2 2 3 3 1 3 2 3 3

By passing true in while condition, infinite do while loop is executed. Its execution can be stopped by using ctrl + c.

Example

snippet

do{
   printf "Infinitive do-while Loop\n";
}while( true );

Output

Infinitive While Loop Infinitive While Loop Infinitive While Loop Infinitive While Loop Infinitive While Loop ctrl+c