[转]算法课上老师给的标准，用来参考，其实最重要的是态度[

1 int binarySearch(int *arr, int left, int right, int val) {
2     int mid = 0;
3     if (left > right)
4         return -1;
5     else
6         mid = (left + right) / 2;
7
8     if (val == arr[mid])
9         return mid;
10     else if (val < arr[mid])
11         return binarySearch(arr, left, (mid - 1), val);
12     else
13         return binarySearch(arr, (mid + 1), right, val);
14 }