use strict;
my $number=0;  
my $line;  
my $score;  
my $std;  
my $avg;  
my $name;  
my $sum;
my $totd; 

open(IN, "pa5c.dat") || die ("Can't open file $!\n");
while($line = <IN>){
		chomp($line);
		++$number;
		($name, $score) = split(/:/, $line);
		$sum = $sum + $score;
		
		$totd += abs($sum - $avg);	
		$std = $totd / $number;
}

$avg = $sum / $number;
printf "The class average is:  %3.1f\n", $avg;
printf "The standard deviation is:  %3.1f\n", $std;

__END__#pa5.pl