Modulus operator, unexpected results

[Poster]

Hi, I am having a little trouble with a sub that is using the modulus
operator.

It is called here-within a while loop:
while (my $row = $sth-fetchrow_hashref()) {
count++;
color_rows( $count )
--some other stuff
td bgcolor=$bgcolortable cell value/td
-some other stuff
}
--here is the sub
sub color_rows
{
my $num = @_;
my $bgcolor;

If ( $num % 2 == 0 ) {
$bgcolor=#bde6de;
} else {
$bgcolor=white;
}
return $bgcolor;
}#end sub

I expect that when the value that is passed in $count is even it will
set the row color green, otherwise it will set it to white. What it is
actually doing is setting the value white every time. 

Thanks.

Ramon Hildreth

 
---
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Re: Modulus operator, unexpected results

[Sudarshan Raghavan]

On Fri, 22 Nov 2002, Poster wrote:

 Hi, I am having a little trouble with a sub that is using the modulus
 operator.
 
 It is called here-within a while loop:
 while (my $row = $sth-fetchrow_hashref()) {
   count++;
   color_rows( $count )
   --some other stuff
   td bgcolor=$bgcolortable cell value/td
   -some other stuff
 }
 --here is the sub
 sub color_rows
 {
 my $num = @_;

This statement assigns the number of elements in @_(no of arguments passed 
into the sub) into $num. In your case $num will always contain 1.

This should be 
my $num = $_[0];
or
my $num = shift;


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Re: Modulus operator, unexpected results

[Jeff 'japhy' Pinyan]

On Nov 22, Poster said:

Hi, I am having a little trouble with a sub that is using the modulus
operator.

No, your function is written incorrectly, and you don't use it correctly.

while (my $row = $sth-fetchrow_hashref()) {
   count++;
   color_rows( $count )
   --some other stuff
   td bgcolor=$bgcolortable cell value/td
   -some other stuff
}

sub color_rows {
my $num = @_;

First mistake is that line.  That assigns the NUMBER of elements in @_ to
$num.  Use one of the following methods:

  my $num = shift;
  # or
  my ($num) = @_;

my $bgcolor;

Your while loop can't see this variable.

if ( $num % 2 == 0 ) {
   $bgcolor=#bde6de;
} else {
   $bgcolor=white;
}
return $bgcolor;
}#end sub

If you're returning a value, USE it:

  while (...) {
my $bg = color_rows($count++);
print qq{td bgcolor=$bg.../td};
  }

There's no need for a function, though.

  while (...) {
my $bg = $count++ % 2 ? #bde6de : #ff;
# ...
  }

-- 
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RPI Acacia brother #734   http://www.perlmonks.org/   http://www.cpan.org/
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[  I'm looking for programming work.  If you like my work, let me know.  ]


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