#!/usr/local/bin/perl
use strict;
use warnings;

my %operators = (
  '+' => sub { $_[0] + $_[1] },
  '-' => sub { $_[0] - $_[1] },
  '*' => sub { $_[0] * $_[1] },
  '/' => sub { $_[0] / $_[1] }
);

$|++; # Flush output automatically

print 'First operand:  ';
chomp (my $operand1 = <>);

print 'Operator:       ';
chomp(my $symbol = <>);

print 'Second operand: ';
chomp(my $operand2 = <>);

die "Unknown operator $symbol\n" if (!exists $operators{$symbol});

print "----------------\nResult:         ",
      $operators{$symbol}->($operand1, $operand2),
      "\n";