二分查找——递归和非递归

#include <iostream>
#include <assert.h>
using namespace std;
//二分查找，非递归形式
int binarySearch(int *a, int b, int e, int v)  
{  
	assert(a != NULL);
    int *begin = a+b;
	int *end = a+e;
	int *mid;  
	//异常处理
    if (!a || b >= e) 
	{
		return -1;  
	}
	//折半查找
    while (begin < end)  
    {  
        mid = begin + ((end - begin) >> 1);  
        assert(*begin <= *mid && *mid <= *end);  
        if (*mid > v) 
		{
			end = mid;  
		}
        else if (*mid < v) 
		{
			begin = mid + 1;  
		}
        else 
		{
			return mid - a;  
		}
    }  
    return -1;  
}  
//递归实现二分查找
int BinSearch(int Array[],int low,int high,int key/*要找的值*/)
{
	assert(Array != NULL);
	if (low<=high)
	{
		int mid = (low+high)>>1;
		if(key == Array[mid])
		{
			return mid;
		}
		else if(key<Array[mid])
		{
			return BinSearch(Array,low,mid-1,key);
		}
		else if(key>Array[mid])
		{
			return BinSearch(Array,mid+1,high,key);
		}
	}
	else
	{
		return -1;
	}
}

void main()
{
	int a[10] = {1,2,3,4,5,6,7,8,9,10};
	int b = BinSearch(a,0,9,6);
	cout << b <<endl;
}