executing php on wordpress

I have a wordpress website, and i wanna execute my php code on my wordpress. my php code does web crawling. Can anyone guide me on how to run my code on wordpress, i've tried using plugins such as insert php, global content blocker and exec-php, but i keep on getting errors.

  <?php

$to_crawl ="http://eklas.msu.edu.my.com";
$c = array();

function get_links($url) {
global $c;
$input = @file_get_contents($url);
$regexp = "<a\s[^>]*href=(\"??)([^\" >]*?)\\1[^>]*>(.*)<\/a>";
preg_match_all("/$regexp/siU",$input,$matches);
$base_url = parse_url($url, PHP_URL_HOST);
$l = $matches[2];

foreach($l as $link){

    if (strpos($link, "#")){
        $link = substr($link, 0, strpos($link, "#"));   
    }

    if (substr($link,0,1) == ".") {
        $link = substr($link, 1);
    }

    if (substr($link, 0, 7)== "http://"){
            $link = $link;
        }else if (substr($link, 0, 8)== "https://"){
            $link = $link;
        }else if (substr($link, 0, 2)== "//"){
            $link = substr($link, 2);
        }else if (substr($link, 0, 1)== "#"){
            $link = $url;
        }else if (substr($link, 0, 7)== "mailto:"){
            $link = "[".$link."]";
        } else{
            if (substr($link, 0, 1) != "/") {
                $link = $base_url."/".$link;
            } else {
                $link = $base_url.$link;
            }
        }

        if (substr($link, 0, 7) != "http://" && substr($link, 0, 8) != "https://" && substr($link, 0, 1) != "["){
            if (substr($url, 0, 8) == "https://") {
                $link = "https://".$link;
            }else {
                $link = "http://".$link;
            }
        }


        //echo $link."<br />";
        if (!in_array($link, $c)){
            array_push($c, $link);
        }
    }   
}

get_links($to_crawl);

foreach ($c as $page){
//get_links($page);
echo $page."<br />";
}

//foreach ($c as $page){

// echo $page."
"; //} ?>