Banner Rotator

[markster]

How would I go about creating a banner rotator through which i could controll the probablility of an ad appearing? I can create a script to display a random ad each time, but I'm not sure on creating a script with probability. I though the array of ads would look like this:

PHP Code:

# $banners = array("link","img",probability);
$banners = array("banner1.php","banner1.gif",0.5);
$banners = array("banner2.php","banner2.gif",0.25);
$banners = array("banner3.php","banner3.gif",0.25); 


In this example banner 1 would be shown half the time, and banner 2 and 3 a quarter of the time. I'm just not sure how the rest would work

Please help if you have a rough idea.

[teknomage1]

You could do something like this:

PHP Code:

$randVal = rand(1,100)/100;
$done = 0;
$counter = 0;
while(!$done){
    $prob = $banners[$counter][2];
    if($prob < $randVal){
        $done = 1;
    }
    else {
       $counter++;
       $randVal = $randVal - $prob;
    }
}
someFunctionToDisplay($banners[$counter]); 


*Note: I typed this straight into the text box and my php is a little rusty so this code probably needs some love, but it should demonstrate the basic idea.