1 // 递归算法 2 int BinarySearch(int item, Node *elem, int left, int right) 3 { 4     int mid = -1; 5     if(left <= right) { 6         mid = (left + right) / 2; 7         if(elem.val < item)  8             mid = BinarySearch(item, elem, (mid + 1), right); 9         else if(elem.val > item)10             mid = BinarySearch(item, elem, left, (mid - 1));11     }12     return mid;13 }14 15 // 非递归算法16 int BinarySearch(int item, Node *elem, int len)17 {18     int left = 0, right = len - 1, mid = -1;19     while(left <= right) {20         mid = (left + right) / 2;21         if(elem.val < item)22             left = mid + 1;23         else if(elem.val > item)24             right = mid - 1;25         else26             return mid;27     }28     return NOFOUND;29 }