while defined (...) {

##</code><code>##

while (defined ...) {

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

my $scoreFile = "high_score.dat";
open my $inFile, '<', $scoreFile or die "Can't open $scoreFile: $!\n";

Forever: while (1) {
    while (defined(my $score = <$inFile>)) {
        print "$score\n";
    }

    my $num   = int(1 + rand 100);
    my $count = 0;
    print "If you want to exit type 'quit' or 'exit' or leave a blank line\n";

    while (1) {
        $count++;
        print "Guess a num: ";
        chomp(my $guess = <STDIN>);
        if ($guess == $num) {
            print "Right!!!.\n";
            print "enter your name: ";
            chomp(my $name = <STDIN>);
            while (defined(my $line = <$inFile>)) {
                if ($line =~ /^($name)/) {
                    $line =~ s/\d+$/$count/;
                } else {
                    open $inFile, $scoreFile
                        or die "Can't reopen $scoreFile: $!\n";
                    print $inFile "$name has the score of $count\n";
                }
            }

            print "You took $count chances to complete\n";
            next;
        }

        last Forever if $guess =~ /^(exit||quit||\n)$/;

        if ($guess > $num) {
            print "High!!!. Go lower \n";
        } else {
            print "Low!!!. Go higher \n";
        }

        redo;
    }
}

print "Thank you for playing my game\n";