<?php
/**
* Recursive function to convert a decimal number to binary
*
* @param int $dec number to convert
* @return string
*/
function decToBin(int $dec, string $result = "")
{
if($dec == 0) return $result;
$result = (string)($dec % 2) . $result;
return (int)decToBin($dec / 2, $result);
}
print decToBin(200);