{
  my $input = '';
  while( $input ne 'c' && $input ne 'C' ) {
    print "Press C to continue\n";
    $input = <STDIN>;
    chomp $input;
  }
}
print "It worked, of course.\n";
[download]

I would probably turn the Boolean expression into $input !~ /^c$/i, but your class probably hasn't gotten to regexes yet.

If this is not homework, prompting made easy:

use IO::Prompt::Hooked;
my $input = prompt(
  message  => 'Press c to continue.',
  validate => qr/^c$/i,
);
print "It worked, of course.\n";
[download]

...of if you never need to look at $input again:

use IO::Prompt::Hooked;
prompt(
  message  => 'Press c to continue.',
  validate => qr/^c$/i,
);
print "If we're here, we know it worked.\n";
[download]