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

hi, I am working on my final for my perl class and have almost finished. it is a voting script, it all works fine except for when it needs to increment the new votes that are in the text file. the candidate labeled $vote1 will increment with no problem but the remaining 8 candidates will only be written to as 1 if voted for and the vote will be written over instead of added to if another voter uses the script. I believe it is something to do with the while loop and I have tried a number of combination and the foreach command instead. there is a comment about the problem right above it and is located near the end of the script

#!/usr/bin/perl

use CGI ':standard';


print header;


$prez=param('prez');
$vice=param('vice');
$secretary=param('secretary');
$count = 1;

print "PREZ " . $prez ."<br>";
print "vice " . $vice . "<br>";
print "secretary " . $secretary . "<HR>";

#this opens the voting text file and extracts the information
open (VOTE, "<vote.txt");
while(<VOTE>){
    ($user[$count],$vote[$count])=split (/\|/);
    $count++
}
close VOTE;

#the variables for prez,vice and secretary are compared to these names
+ and increment there count by one for each vote they recieve
if ($prez eq 'sam'){
    $vote[1]++;
}
if ($prez eq 'hosea'){
    $vote[8]++;
}
if ($prez eq 'howard'){
    $vote[6]++;
}

if($vice eq 'wendy'){
    $vote[7]++;
}
if($vice eq 'ann'){
    $vote[3]++;
}
if($vice eq 'george'){
    $vote[2]++;
}


if($secretary eq 'martha'){
    $vote[5]++;
}
if($secretary eq 'tom'){
    $vote[4]++;
}
if($secretary eq 'david'){
    $vote[9]++;
}

$count = 1;
#this is suppose to be the while loop which runs $vote[1] to #vote[9],
+ but it only saves the data for sam because he is $vote[1] all others
+ will show as a count of one if voted for, but will not increment if 
+voted for again
open VOTE, ">vote.txt";
while (10 > $count){
    print VOTE $user[$count]."|".$vote[$count];
    $count++;
}
close VOTE;

#this displays the vote tally for each candidate
print "sam has $vote[1] votes<br>";
print "hosea has $vote[8] votes<br>";
print "howard has $vote[6] votes<br>";
print "wendy has $vote[7] votes<br>";
print "ann has $vote[3] votes<br>";
print "george has $vote[2] votes<br>";
print "martha has $vote[5] votes<br>";
print "tom has $vote[4] votes<br>";
print "david has $vote[9] votes<br>";
print " @vote";
print "<a href=backhome.cgi>main page</a>";

[download]

there are two scripts before this one that verify a password and allow the user to vote that work fine it is just the retention of the votes in the text file that doesn't work, I also need a way to prevent them from using the back button to vote again. it isn't a requirement but I would like to do it right. thank you for your time

Replies are listed 'Best First'.
Re: incrementing array variables in a text file?
by wind (Priest) on Apr 30, 2011 at 20:09 UTC
    Use a hash to store the votes. 
    my %votes;

my $file = 'vote.txt';
open my $ih, $file or die $!
while (<$ih>) {
    chomp;
    my ($user, $count) = split ',';
    $votes{$user} = $count;
}
close $ih;

$votes{sam}++;

open my $oh, $file or die $!
for my $user (keys %votes) {
    print $oh "$user,$votes{$user}\n";
}
close $oh;

    [download]

    On a side note, your code wasn't working because you weren't outputted a return for each record:

    # From
print VOTE $user[$count]."|".$vote[$count];

# To
print VOTE $user[$count]."|".$vote[$count]."\n";

    [download]
[reply]
[d/l]
[select]

      thanks for the help the "\n" was a good idea and I thought it was working but if you vote more then twice it starts moving the text file around and changing the votes.

      First vote

      |
|
|1
|1
|
|
|
|1
|

      [download]

      second vote

      |

|

|2
|2
|

|

|

|2
|

      [download]

      third vote

      |


|
|1

|1
|2

|2

|


|1
|

      [download]

      all three votes were for the same three people but it seems to start spreading them out. is there a certain way I need to setup the text file so it doesn't do this? I tried the hashes too but they didnt work for me probably because I never learned them and just don't understand the concept

[reply]
[d/l]
[select]

        %hashes are unordered @array's where the keys are strings instead of integers. Learn them. They are the most important part of perl that you should be learning.

        I already showed you the code for reading and writing the votes in a %hash data structure to a file.

        Also, add use strict; and use warnings; to the beginning of your script, and since this is CGI, CGI::Carp as well.

        use CGI ':standard';
use CGI::Carp qw(fatalsToBrowser);

use strict;
use warnings;

        [download]
[reply]
[d/l]
        Remove the "\n" when you read the records in 
        while(<VOTE>){
  chomp ; # add
 ($user[$count],$vote[$count])=split (/\|/);
  $count++
}

        [download]
        poj
[reply]
[d/l]

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