#!/usr/bin/perl -w
print "Your binary input please =>";
$bin = <STDIN>; #read in user input 
chomp $bin;

# use of array to store $bin and split it
@digits = reverse(split('',$bin)); #reverse and split $bin, then assign to an array
$result = 0;

foreach $pos (0..$#digits) {
$result += $digits[$pos] * 2 ** $pos; 
} 

print $result;