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<?php/*
 1. Validation:   Check input data in proper form.
 2. Sanitization: Remove illegal character from input data.
 
 A. filter_var(variable, filter, options) -> This functions validate and sanitize the input.
 */
 
 // input data
 $input_roll = 120;
 
 // Remove all illegal characters from input data
 $input_roll = filter_var($input_roll, FILTER_SANITIZE_URL);
 
 // Validate sample integer value
 if(filter_var($input_roll, FILTER_VALIDATE_INT)){
 echo "<br /> The <b>$input_roll</b> is a valid integer";
 } else {
 echo "<br /> The <b>$input_roll</b> is not a valid integer";
 }
 
 
 // Validate sample integer value with options
 
 $min = 1;
 $max = 200;
 
 if (filter_var($input_roll, FILTER_VALIDATE_INT, array("options" => array("min_range"=>$min, "max_range"=>$max))) === false) {
 echo ("<br /> The <b>$input_roll</b> is a not valid integer || not within the legal range");
 } else {
 echo ("<br /> The <b>$input_roll</b> is a valid integer & within the legal range");
 }
 
 
 // Validate url with query parameter
 
 $url = "https://www.w3schools.com?id=5"; // validated
 //$url = "https://www.w3schools.com"; // not valdated
 
 if (!filter_var($url, FILTER_VALIDATE_URL, FILTER_FLAG_QUERY_REQUIRED) === false) {
 echo("<br />$url is a valid URL with a query string");
 } else {
 echo("<br />$url is not a valid URL with a query string");
 }
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