Finding average using package subroutine

[pinnacle]

package

package Average; # D e c l a r e  a  p a c k a g e
                # A v e r a ge  a  l i s t  o f  g r a d e s

sub av {
$total = 0;
@grades = (3,4,5);

$num_of_grades =$#grades + 1;
foreach $grade ( @grades ) {
     $total += $grade;
}
 $res = $total/$num_of_grades;   #  W h a t  g e t s  r e t u r n e d
#print $res;
return;
}
#&av;

My perl script which calls above package

#!/usr/bin/perl

use warnings;
use Average;

$d = Average::av($res);
print $d;

When I run my script it gives me an error as stated below, I am missing some basic thing, please assist

Name "main::res" used only once: possible typo at ./ave.pl line 6.
Use of uninitialized value $d in print at ./ave.pl line 7.

[toolic]

If you make the following changes, it should print "4":

package Average; # D e c l a r e  a  p a c k a g e
                # A v e r a ge  a  l i s t  o f  g r a d e s
sub av {
$total = 0;
@grades = (3,4,5);

$num_of_grades =$#grades + 1;
foreach $grade ( @grades ) {
     $total += $grade;
}
 $res = $total/$num_of_grades;   #  W h a t  g e t s  r e t u r n e d
#print $res;
return $res;
}

1;
#&av;

...and your script...

use warnings;
use Average;

$res = Average::av();
print $res;

You really meant to return a value ($res) from your sub. Eventually, you will probably also want to pass something as an argument to your sub. See also:

• perlsub
• perlmod
• use strict and warnings
• perltidy
• Acme::Tools::avg

[boom.roasted]

I'm sort of teaching myself perl and have a similar problem. I used the problem above but I'm not getting the same results. I want to find the average using a <STDIN> and subroutines.

here's what I've got:

sub:

sub avg {
$n = 0;
@array = (<STDIN>);


$total =$#array + 1;

foreach $array ( @array ) {
$n += $array;
}
$res = $n/$total;
return $res;
}

1;

function:
#!/usr/bin/perl

require 'obj13-lib.pl';

$res = avg();
print $res;

Where am I going wrong?

[toolic]

Where am I going wrong?

You didn't describe the problem you are having. When I run your code, it seems to work fine for me. If I input the values 2 and 8, it correctly prints a result of 5.

You'll be better off in the long run if you:

• use strict and warnings
• Use packages/modules.
• Basic debugging checklist
• Use code tags: Writeup Formatting Tips