You're appending to a global variable in html_row. Quit that! :)

You want a new $rowP and $tableP on each subroutine call. Using the -w flag and strict is not just a good idea, it's almost a requirement for CGI scripts in Perl. Here's the fixed code: 

#!/usr/bin/perl -w

use strict;

print "Content-type: text/html\r\n\r\n";

# generate an HTML table of the powers of 2,3 and 4

my @rows = html_row("white"," n ", 
        "nth power of 2",
        "nth power of 3",
        "nth power of 4");

for (0 .. 10) {
    if ($_ % 2) {
        push @rows, html_row("#cccccc",$_,2**$_,3**$_,4**$_);
    } else {
        push @rows, html_row("#ccccff",$_,2**$_,3**$_,4**$_);
    }
}

my $table = html_table(1,"",@rows);
my $table2 = html_table(0,"black",html_row("",$table));
print "Here are the powers of 2, 3 and 4<BR><BR>\n";
print "$table2";

# This subroutine will print out a table row
sub html_row {
    my $color = shift;
    my $rowP = "<TR BGCOLOR=$color><TD>";
    $rowP .= join("</TD><TD>", @_) . "</TD></TR>\n";
    return $rowP;
}

# This subroutine will print out an HTML Table    
sub html_table {
    my $border = shift;
    my $color = shift;
    my $tableP ="<TABLE BORDER=$border BGCOLOR=$color>\n";
    $tableP .= join('', @_) . "</TABLE>\n";
    return $tableP;
}

[download]
Note that this code is a lot shorter, and makes use of happy magic variables like @_.

The biggest change is declaring all of the variables with my. This is what fixed your error. Oh, and the closing table tag bug is fixed in my version too.

In reply to Re: HTML Table Using Perl by chromatic
in thread HTML Table Using Perl by Kiko

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