#include<iostream>
using namespace std;
/*
本段程式，實現的是非遞迴的實現二分查詢演算法；
易錯點是low和high的重新定位，以及*array是引用關係；
*/
int BinarySearch(int *array, int ArraySize, int key){
    if (array == NULL || ArraySize == 0)
        return -1;
    int low, high, mid=0;
    low = 0; high = ArraySize - 1;
    while (low <= high){
        mid = (low + high) / 2
 
;
        if (array[mid] < key)
            low = mid + 1;
        else if (array[mid] > key)
            high = mid - 1;
        else
            return mid;
    }
    return -1;
}
int main(){
    int n,key, array[100],key_pos;
    cout << "輸入個數n=" << endl;
    cin >> n;
    cout
 
 << "輸入關鍵字:" << endl;
    cin >> key;
    cout << "輸入要搜尋的n個數：" << endl;
    for (int i = 0; i < n; i++)
        cin >> array[i];
    //key_pos = BinarySearch(array, n, key);
    cout << "The pos is  " << BinarySearch(array, n, key) << endl;
    return
 
 0;
}