I noticed a few problems with that script you plan to use.
1. If there are no results you will get a divide by zero error.
2. If all results are equal the result will read 3.3333333333333....
3. Image widths should be integers.
4. Users accessing the script similtaneously will cause erroneous results.
Here's a commented rewrite for you to review with some tpis for writing .cgi scripts in the future.
This is only tested for syntax but should work for you, if you so choose.
I've commented out the file lock because it does not work on older versions of Perl.
If you copy and paste this, MAKE SURE the that last line 'HTML_OUTPUT' does NOT contain a space at the end.
#!/usr/bin/perl
use strict; ## ALWAYS use strict
use CGI; ## Use this module (comes with the Perl distrubution) to get 'post' and 'get' data
my $q = new CGI;
## If the file does not exist, then create it with a 0,0,0 result
unless (-e "poll.dat") {
open(POLL, ">poll.dat") || die "Cannot create poll.dat: $!";
print POLL "0\t0\t0\n";
close(POLL);
}
## Open (and lock) the file for read and write
open(POLL, "+<poll.dat") || die "Cannot open poll.dat: $!";
#flock(POLL, 2) || die "Cannot lock poll.dat: $!"; ## not supported on all systems.
my $poll_data = <POLL>; ## only reading one line here!
chomp $poll_data;
## Seperate the results into an array
my @poll_results = split(/\t/, $poll_data);
## Using CGI, get the results from the latest poll response and add to current results.
if ($q->param('QUESTION') eq "yes") { $poll_results[0]++; }
elsif ($q->param('QUESTION') eq "no") { $poll_results[1]++; }
elsif ($q->param('QUESTION') eq "narf") { $poll_results[2]++; }
## Save the updated results.
print POLL "$poll_results[0]\t$poll_results[1]\t$poll_results[2]\n";
close(POLL);
## Declare a set of default results
my @yes_result = (0,1);
my @no_result = (0,1);
my @maybe_result = (0,1);
my $total_answers = $poll_results[0] + $poll_results[1] + $poll_results[2];
## Do not allow a divide by zero
if ($total_answers > 0) {
if ($poll_results[0] > 0) { ## Only do this if there are some results othewise use the default
## Format the precentage to xx.x%
$yes_result[0] = sprintf("%.1f", ($poll_results[0] / $total_answers)*100);
## Use an integer for the width with a minium of 1
$yes_result[1] = int($yes_result[0] + 1);
}
if ($poll_results[1] > 0) {
$no_result[0] = sprintf("%.1f", ($poll_results[1] / $total_answers)*100);
$no_result[1] = int($no_result[0] + 1);
}
if ($poll_results[2] > 0) {
$maybe_result[0] = sprintf("%.1f", ($poll_results[2] / $total_answers)*100);
$maybe_result[1] = int($maybe_result[0] + 1);
}
}
## Try to keep your Perl and HTML seperated as much as possible. Much easier to debug
## Output the HTML page using a 'here-is' construct.
print "Content-type: text/html\n\n";
print <<HTML_OUTPUT;
<HTML><HEAD><TITLE>POLL RESULTS</TITLE></HEAD>
<BODY BGCOLOR=FFFFCC>
<CENTER><H2>Poll Results</H2></CENTER>
<h3>Would You Go To The North Poll?</h3><BR>
<TABLE BORDER=1 cellpadding=5 cellspacing=1>
<TR><TD><b>Answer</b></TD><TD><b>Number</b></TD><TD><b>Percentage</b></TD><TD><b>Visual</b></TD></TR>
<TR><TD>Yes:</TD><TD>$poll_results[0]</TD><TD>$yes_result[0]%</TD>
<TD><IMG SRC="/Poll/pollred.gif" width=$yes_result[1] height=7 ALT=Yes answers></TD></TR>
<TR><TD>No:</TD><TD>$poll_results[1]</TD><TD>$no_result[0]%</TD>
<TD><IMG SRC="/Poll/pollred.gif" width=$no_result[1] height=7 ALT=No answers></TD></TR>
<TR><TD>Maybe:</TD><TD>$poll_results[2]</TD><TD>$maybe_result[0]%</TD>
<TD><IMG SRC="/Poll/pollred.gif" width=$maybe_result[1] height=7 ALT=Maybe answers></TD></TR>
<TR><TD colspan=4>Total Number of Answers: $total_answers</TD></TR>
</TABLE>
</BODY>
</HTML>
HTML_OUTPUT
QUERY :confused:
Why is there a 'return' in this line?
print POLL " $poll_results[0]\t$poll_results[1]\t$poll_results[2]\n";