given when default statement in perl-IGI

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In Perl, the given-when statement allows you to test a variable against multiple values and execute different blocks of code based on the value of the variable. The default block is optional and is executed if none of the when blocks match the variable. The syntax for given-when with default statement in Perl is:

given (expression) {
    when (value1) {
        # code to execute when expression is equal to value1
    }
    when (value2) {
        # code to execute when expression is equal to value2
    }
    ...
    default {
        # code to execute when expression doesn't match any when clause
    }
}

Here's an example to demonstrate how given-when with default statement works:

my $fruit = "apple";

given ($fruit) {
    when ("apple") {
        print "It's an apple.\n";
    }
    when ("banana") {
        print "It's a banana.\n";
    }
    default {
        print "It's not an apple or a banana.\n";
    }
}

In this example, the given statement takes a variable $fruit as its argument, and the when statements test the value of $fruit against different strings. If $fruit matches a string, the code inside the corresponding when block is executed. If none of the when blocks match, the default block is executed.

If $fruit were "apple", the output would be:

It's an apple.

If $fruit were "banana", the output would be:

It's a banana.

If $fruit were any other value, the output would be:

It's not an apple or a banana.

Note that the given-when statement was introduced in Perl 5.10, so if you're using an older version of Perl, you won't be able to use this syntax. In older versions of Perl, you can use if-elsif-else statements to achieve similar functionality.

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given when default statement in perl