二分查找算法

//
//  BinarySearch.c
//  libin
//
//  Created by 李宾 on 16/4/28.
//  Copyright © 2016年 李宾. All rights reserved.
//

#include <stdio.h>
//非递归
int Binary_Search(int a[], int low, int high, int key)
{
    while (low <= high)
    {
        int mid = (low + high)/2;
        if(a[mid] == key)
        {
            return mid;
        }
        else if(a[mid] < key)
        {
            low = mid + 1;
        }
        else
            high = mid - 1;
    }
    return -1;
}


//递归
int Binary_Search1(int a[], int low, int high, int key)
{
　　if(low > high)
　　{
　　　　return -1;
　　}
   int mid = (low + high)/2;

　　if (a[mid] == key ) 
　 {
       return mid;
   }
   else if(a[mid] < key)
   {
       return Binary_Search1(a, mid+1, high, key);
   }
   else
       return Binary_Search1(a, mid, high-1, key);
   }
}
int main()
{
    int a[6] = {1, 23, 33, 45, 56, 65};
    Binary_Search1(a, 0, 5, 34);
    
}