My issue isn't strict, I don't know why everyone says that.

Because you write $main::c and other $main:: stuff

You wrote $main::hd to stop strict from complaining but that is a package/global variable

The solution was use lexical variables  my $hd = ...;

Also you should avoid one letter variables, especially $a and $b, they're special

If you're interested :) Tutorials: Variable Scoping in Perl: the basics,
Coping with Scoping , Mini-Tutorial: Perl's Memory Management,
Lexical scoping like a fox,