二分查找

#include <iostream>
#include <cstdio>

using namespace std;

int binarySearch(const int *Array, int start, int end, int key)
{
    int left, right, mid;
    left = start;
    right = end;

    while(left <= right){
       mid = (left + right) >> 1;
       if(Array[mid] == key) return mid;

       if(Array[mid] > key) right = mid - 1;
       else left = mid + 1;
    }

    return -1;
}


int main()
{
    int a[10] = {0,1,2,3,4,5,6,7,8,9};

    cout << binarySearch(a,0,9,12);

    return 0;
}