How can I limit the max value of number?

Question

I want to secure my page by checking if the value is digital (0,1,2,3) and if it is in the range from 0 to 120. I think ctype_digit function limits numbers, so

Answer 1

// Make sure it is an integer.
$category = (int) $_GET['category'];

if($category<0 OR $category>120){
   // Code to be executed if the number is out of range...
}