File::Find is your friend.

use File::Find;

find(\&process, qw(C:/foo C:/bar));

sub process {
    return unless /\.(?:h|c|cpp)\z/ and -f $File::Find::name;
    open FH, "+<", $File::Find::name;
    s/$some_character// while <FH>;
    close FH;
}
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Makeshifts last the longest.