#!c:\Program Files\Perl\perl 

$count = 0;

print "\n\nThis PERL program calculates the AVERAGE GPA of a list ";
print "of students. To exit type \"DONE\"!!!\n\n";

do	{	print "Enter {$count}-th student's Name: ";
		chomp($name=<STDIN>);
		if ($name ne "DONE" && $name ne "done")
		{   
			print "Enter {$name}'s GPA: ";
			chomp($GPA=<STDIN>);

			while ( 0> $GPA || $GPA >4)
			{	print "Enter {$name}'s GPA in the ";
				print " range [0 : 4]: ";
				chomp($string=<STDIN>);
				print "string=$string";
			 }
   
			# make a hash table storing student's name & GPA
			$name_2_GPA{$name} = $GPA;
			
			$count++;
		 }
	}
	while ($name ne "DONE" && $name ne "done");


@grades = sort(values % name_2_GPA);

$lowestGPA = $grades[0];
$highestGPA = $grades[count-1];

if ($count >0) { print "\n\nThe highest GPA is: $highestGPA\n"; }

if ($count >1) { print "\tThe Lowest GPA is: $lowestGPA\n\n\n"; }