array does not accept more than one number

bluethundr has asked for the wisdom of the Perl Monks concerning the following question:

oh hai, monks.

I am re-trying my hand at perl and going through the Lllama one more time.

I'm attempting exercise 3 on chapter 4.

here's what I came up with:

-------------------

#!/usr/bin/perl -w
use strict;

sub avg {

   my $total;
   foreach (@_) {

   $total += $_;

  }
  print "This is the value of \$total: $total \n ";
  my $num = (@_);
  print "This is the value of \$num: $num \n";
  return $total / $num;
}

sub above_avg {
    my $tot_avg = &avg(@_);
    print "This is the value of \$tot_avg $tot_avg \n";
    my @product;
    foreach (@_) {
      if ($_ > $tot_avg) {
         (@product)  = $_;
      }
    }
   print "This is the value of \@product @product \n";
   return @product;
}
   
print "Please enter a series of numbers: ";
my @entered = (<STDIN>);
print "Here are the numbers above the average: ", &above_avg(@entered)
+, "\n";
[download]

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The assignment is to produce a list of numbers that are above the average of a set of numbers input by the user.

For some reason, my array (@product) doesn't seem to be acting like an array. It only accepts ONE number instead of however many are above the average. Any hints?

Thanks!

Comment on array does not accept more than one number Download Code

Replies are listed 'Best First'.
Re: array does not accept more than one number by ikegami (Patriarch) on Dec 09, 2008 at 23:55 UTC
Assignments (as in "`@product = ...;`") replace the current contents of the variable to which data is being assigned. You need `push` here. As an extra exercise, you should replace "`foreach (@_) { if ($_ > $tot_avg) { ... } }`" with a call to `grep`. You should also look into separating I/O from computation. `avg` and `above_avg` shouldn't print anything. Why are you using "`&`" in front of subroutine calls? That tells Perl to ignore the subroutine's prototype. Do you have a reason to do that?	[reply] [d/l] [select]
Re^2: array does not accept more than one number by Bloodnok (Vicar) on Dec 10, 2008 at 11:41 UTC
Hi ikegami, I think your point about mixing computation & I/O may be a little unkind to the poster - methinx the OP contained the (admittedly primitive, but nonetheless effective) debug inserted whilst attempting to answer the question for themselves - shortly after which, they gave up and asked for help. That being said, ++ for the `&` hint - I didn't realise that - not that I use it anyway. A user level that continues to overstate my experience :-))	[reply] [d/l]
Re: array does not accept more than one number by graff (Chancellor) on Dec 10, 2008 at 02:34 UTC
ikegami is right (as usual). On top of what he said, some checking of values would be a good idea, to avoid unsightly crashes (like "divide by zero"). Suppose that you just fix the assignment to @product (using "push" as suggested in the first reply). Then run the script like this: `$ your_script ^D` [download] (or "^Z", if you're using MS-windows/DOS-Prompt -- cmd.exe or command.exe -- instead of a linux/unix/macosx shell / bash for windows) What happens? My point is: check what $num is before you use it for division.	[reply] [d/l]