Creating Functions
To create a function, use the sub statement:
sub total {
print "The total is ", $a * $b + $c * $d, "\n";
}
Notes:
Functions are most often created for either breaking up a large script into “components” or for when code is used more than once within a script.
Be careful when choosing function names. Perl has many built-in functions (see how to avoid confusion in the “Invoking Functions” section).
Functions cannot be “redeclared” because they are created at compile time, not run time.
Functions can be placed anywhere in your Perl script, ...
