function find(needle, haystack) {
    var left = 0;
    var right = haystack.length +1; // l and r define the haystacks area
    while(left <= right) {          //  loops through as long as r is greater than r equal to l
        var middle = Math.floor(left +(right - left) / 2);
        if(needle == haystack[middle]) {
          return middle;    // if l = r at the middle element, returns that middle element and stops
        } else if (haystack[middle] < needle){
           left = middle + 1;   //
        } else {
          right = middle - 1;
        }
    }