#include <iostream>

using namespace std;

/*
*二分查詢思想：1、陣列從小到大排序；2、查詢的key每次和中間數比較，如果key小於mid
查詢mid左側的陣列部分；如果key大於mid，則查詢mid右側的陣列部分；如果相等，則直接返回mid。

輸入：排序陣列-array,陣列大小-aSize,查詢值-key
返回：返回陣列中的相應位置，否則返回-1
*/
//非遞迴查詢
int BinarySearch(int *array, int aSize, int key)
{
    if ( array == NULL || aSize == 0
 
 )
        return -1;
    int low = 0;
    int high = aSize - 1;
    int mid = 0;

    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;
}
//遞迴
int BinarySearchRecursive(int *array, int low, int high, int key)
{
    if ( low > high )
        return -1;
    int mid = ( low + high )/2;

    if ( array[mid] == key )
        return mid;
    else if ( array[mid] < key )
        return BinarySearchRecursive(array
 
, mid+1, high, key);
    else
        return BinarySearchRecursive(array, low, mid-1, key);
}

int main()
{
    int array[10];
    for (int i=0; i<10; i++)
        array[i] = i;

    cout<<"No recursive:"<<endl;
    cout<<"position:"<<BinarySearch(array, 10, 6)<<endl;
    cout<<"recursive:"<<endl;
    cout<<"position:"<<BinarySearchRecursive(array, 0, 9, 6)<<endl;

    return 0;
}