hangman: more validation (#502)

* An empty wordlist.txt could be provided, in which case hangman should fail because no lines can be read
* Also, there was no code after the read-words loop to check if $word was actually given a value
* Rewrite read-words loop without the need for $line_num variable
* test1: create empty wordlist with "touch wordlist.txt"
* test2: create a list with 1 word: "echo hey > wordlist.txt"

bin/hangman

@@ -73,26 +73,19 @@ print "\nTHANKS FOR PLAYING!\n";
 sub get_a_word {
 	my $wordlist = "wordlist.txt";
 	my( $fh, $word );
-	my( $line_num ) = 1;
 	my( $random ) = rand();
 
 	open($fh, '<', $wordlist) or die "Could not open <$wordlist>: $!\n";
 	my $lines = 0;
 	$lines++ while (<$fh>);
+	die "Empty word list: $wordlist\n" unless $lines;
 	my $val = int($random * $lines) + 1;
-
 	close($fh) or die "Could not close <$wordlist>: $!\n";
-	open($fh, '<', $wordlist) or die "Could not open <$wordlist>: $!\n";
 
-	while( <$fh> ) {
-		if( $line_num == $val ) {
-			$word = $_;
-			chomp( $word );
-			last;
-		} else {
-			$line_num++;
-		}
-	}
+	open($fh, '<', $wordlist) or die "Could not open <$wordlist>: $!\n";
+	$word = <$fh> for (1 .. $val);
+	die "Could not find a word in $wordlist\n" unless defined $word;
+	chomp $word;
 	close($fh) or die "Could not close <$wordlist>: $!\n";
 	return( $word );
 }