巧妙的使用子例程引用

--> #!/usr/bin/perl -w
use strict;

print "Enter operator op1 op2\n";
$_=<STDIN>;
my ($op,$op1,$op2)=split;
my %op_table=(
        "+" => sub{ $_[0] + $_[1]},
        "-" => sub{ $_[0] - $_[1]},
        "*" => sub{ $_[0] * $_[1]},
        "/" => sub{ $_[0] / $_[1]},
);
print "result:";
print &{$op_table{$op}}($op1,$op2),"\n";