mauvis99 has asked for the wisdom of the Perl Monks concerning the following question:

Hi there,

I'm a noob to Perl and just wondering how to add all numbers in an array to give a total using a foreach loop? My code looks like this.. 

#! /usr/bin/perl
#
#
#

use strict;
use warnings;

#------------------data-------------------------
my @Rainfall ;
my $Index ;
my ($Total, $Average) = 0, 0;
#------------------program----------------------

print " Enter 12 numbers for the rainfall for each month \n";

for ( $Index = 0; $Index < 12 ; $Index++ )
{
 print "Enter a month's rainfall: " ;
 chomp($Rainfall[$Index] = <STDIN>);
}

#
# now we have all the input, we can do things with it:
#

foreach (@Rainfall)       

{

$Total = $_;

[download]
This is where im stuck! any help or another way to do this would be much appreciated!

Code tags added by Arunbear

Replies are listed 'Best First'.
Re: Adding Arrays..
by Zaxo (Archbishop) on Mar 29, 2007 at 02:56 UTC

    You'll want parens around "0,0" or you will get a surprise from precedence when you try that with non-zero values. A running total is what you're looking for:

    for (@Rainfall) (
    $Total += $_ ;
}

    [download]

    After Compline,
    Zaxo

[reply]
[d/l]
Re: Adding Arrays..
by dragonchild (Archbishop) on Mar 29, 2007 at 03:17 UTC 
    use List::Util qw( sum );

my $Total = sum @Rainfall;

    [download]
    My criteria for good software:
    1. Does it work?
    2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?
[reply]
[d/l]
Re: Adding Arrays..
by NetWallah (Canon) on Mar 29, 2007 at 06:03 UTC
    Noob style and code suggestions posted here, with your code, formatted: 
    #! /usr/bin/perl
#
#
#

use strict;       # --- Good job on using strict and warnings !!
use warnings;

#------------------data-------------------------
my @Rainfall ;    
my $Index ;       # --- Perl programmers try to avoid using Indexes wh
+ere not necessary.
                  # --- IN This case, Index is NOT necessary
my ($Total, $Average) = 0, 0; # Wrong intent (result would be OK) - er
+ror pointed out by others
#------------------program----------------------

print " Enter 12 numbers for the rainfall for each month \n";

for ( $Index = 0; $Index < 12 ; $Index++ )  # --- Perl programmers wou
+ld not use "C" style loop
{
 print "Enter a month's rainfall: " ;
 chomp($Rainfall[$Index]= <STDIN>);    # ---
}
 
  # --- Perl programmer would have done this like:
  # --- while (<STDIN>){
  # ---    chomp;
  # ---     push @Rainfall, $_;
  # ---  } 

#
# now we have all the input, we can do things with it:
#

foreach (@Rainfall)       

{

$Total = $_; 

  # --- Perl programmer would have done:
  # --- foreach (@Rainfall) {
  # ---    $Total += $_;
  # --- }
  # --- print "Total=$Total;  Average = " , $Total/scalar(@Rainfall) ,
+ "\n"; # Should have formatting for Avg...

    [download]

         "Choose a job you like and you will never have to work a day of your life" - Confucius

[reply]
[d/l]

      $Total += $_ for @Rainfall;

      Some perl programmers do things in different ways. Personally, I think postfix'ed flow controll is one of the sweetest bits of syntatic sugar perl provides.

      drink( $vodca + $orange ) while standing;

      @_=qw; ask f00li5h to appear and remain for a moment of pretend better than a lifetime;;s;;@_[map hex,split'',B204316D8C2A4516DE];;y/05/os/&print;
[reply]
[d/l]
[select]
      Actually, I would use a counted loop because I don't trust users. Also, they don't have to do the counting themselves ....

      Cheers
      Chris

[reply]

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