how to show hit counter then make it back to zero?

i want after i've been submit form it can show hit counter.. but i want after it reach "20" it can back to zero..bcoz the limit of submit is 20 times so it can't over the limit.

how do i make it works?I've been t开发者_高级运维ry to this code...

<?
$limit="20";
$Query_counter=mysql_query("SELECT model FROM inspec");
$Show_counter=mysql_fetch_array($Query_counter);
$show_counter = $show_counter["model"]+1;

if($show_counter > $limit[0]) {
      $show_counter = 0;
}elseif ($show_counter > $limit[1]) {
      $show_counter = 0;
}


$Query_update=mysql_query("UPDATE inspec SET model=$Show_counter");
$Show_counter=number_format($Show_counter);
$Show_counter=str_replace(",",".",$Show_counter);
echo "Hit:</br><strong>$show_counter</strong>";
?>

To make a counter go up to a certain value then loop back to zero, you can use the modulus operator, which in a lot of languages (including PHP and MySQL) is %

$x = 0;
$limit = 4;
for ($i = 0; $i < 10; ++$i) {
    $x = ++$x % $limit;
    echo $x;
}
// 1, 2, 3, 0, 1, 2, 3, 0, 1, 2

I hope that makes enough sense. I can't really figure out from the question what exactly you want... Perhaps something like this?

UPDATE `mytable` SET `mycounter` = (`mycounter` + 1) % {{the limit}}

The concept here is to test to see if the variable you're incrementing exceeds some acceptable range as a result of the next increment. Simple increment the variable, then test its value.

In your case, just add a test after you increment the counter:

$show_counter = $show_counter["model"]+1;
if($show_counter > $limit){
    $show_counter = 0;
}

Be sure to define $limit to whatever number you want to cycle on.

If you want to do this for multiple thresholds you can add additional tests. Note that you could hard-code $limit to any number or any variable you want, it's just the thing you're testing against.

<?
$Query_counter=mysql_query("SELECT model FROM inspec");
$Show_counter=mysql_fetch_array($Query_counter);
$show_counter = $show_counter["model"]+1;

$x = 0;
$limit = 20;
for ($i = 0; $i < 30; ++$i) {
    $x = ++$x % $limit;
    echo $x;
}

$Query_update=mysql_query("UPDATE inspec SET model= (model + 1) % 20");
$Show_counter=number_format($Show_counter);
$Show_counter=str_replace(",",".",$Show_counter);
echo "Hit:</br><strong>$show_counter</strong>";
?>