Operação

operation.pl

#!/usr/bin/env perl

use 5.014;

say "####################################";
say "Program of sum and difference.";
say "####################################";

say "Entre com a opção desejada.";
say "1 - For sum";
say "2 - For difference";
say;
chomp( my $opcao = <STDIN> );

if ( $opcao ne 1 and $opcao ne 2 ) {
	say "Opção inválida";
	exit(1);
} elsif ( $opcao eq 1) {
	print "Please, inform the first number: ";
	chomp( my $num1 = <STDIN> );

	print "Please, inform the second number: ";
	chomp( my $num2 = <STDIN> );
	say &sum($num1,$num2);
} else {
	print "Please, inform the first numbeer: ";
	chomp( my $num1 = <STDIN> );

	print "Please, inform the second number: ";
	chomp( my $num2 = <STDIN> );
	say &dif($num1,$num2);

}

sub sum {
    my $total;
    my @numbers = @_;
    foreach (@numbers) {
        $total += $_;
    }
    return $total;
}

sub dif {
    my $num1 = shift;
    my $num2 = shift;
    return $num1 - $num2;
}