Compare two strings and highlight mismatch characters in Perl

Question

Consider:

string1 = "AAABBBBBCCCCCDDDDD"
string2 = "AEABBBBBCCECCDDDDD"

output. Where the mismatch (in this case E) will be replaced with HTML tags around E that color it.

A**E**ABBBBBCC**E**CCDDDDD

What I tried so far: XOR, diff and substr. First I need to find the indices then replace those indices with the pattern.

Answer 1

my @x = split '', "AAABBBBBCCCCCDDDDD";
my @y = split '', "AEABBBBBCCECCDDDDD";

my $result = join '',
             map { $x[$_] eq $y[$_] ? $y[$_] : "**$y[$_]**" }
             0 .. $#y;

Answer 2

Use:

use strict;
use warnings;

my $string1 = 'AAABBBBBCCCCCDDDDD';
my $string2 = 'AEABBBBBCCECCDDDDD';
my $result = '';
for(0 .. length($string1)) {
    my $char = substr($string2, $_, 1);
    if($char ne substr($string1, $_, 1)) {
        $result .= "**$char**";
    } else {
        $result .= $char;
    }
}
print $result;

It prints A**E**ABBBBBCC**E**CCDDDDD and was tested somewhat, but it may contain errors.