7、递归的二分查找

#include<iostream>

using namespace std;
//迭代二分查找
int BinarySearch_I(int *a,const int x,const int n);
//递归二分查找
int BinarySearch_R(int *a,const int x,const int left,const int right);
int main()
{
	int m[]={1,2,3,4,5,6,7,8,9,10};
	int result;
	int num=7;//要查找的数
	if((result=BinarySearch_I(m,num,9))<0)
	{ cout<<"迭代算法：没找到！"<<endl;}
	else {
		cout<<"迭代算法：在m["<<result<<"]处找到"<<num<<endl;
	}


	if((result=BinarySearch_R(m,num,0,9))<0)
	{ cout<<"递归算法：没找到！"<<endl;}
	else {
		cout<<"递归算法：在m["<<result<<"]处找到"<<num<<endl;
	}
	system("pause");
	return 0;
}
int BinarySearch_I(int *a,const int x,const int n)
{
	int left=0,right=n-1;
	while(left<=right)
	{
		int middle = (left+right)/2;
		if(x<a[middle]) right = middle-1;
		else if(x>a[middle]) left=middle+1;
		else return middle;
	}
	return -1;
}
int BinarySearch_R(int *a,const int x,const int left,const int right)
{
	if(left<=right)
	{
		int middle=(left+right)/2;
		if(x<a[middle]) return BinarySearch_R(a,x,left,middle-1);
		else if(x>a[middle]) return BinarySearch_R(a,x,middle+1,right);
		else return middle;
	}
	return -1;
}

VS2010运行结果：