C++ 二分查找的递归与非递归实现

/*二分查找的递归与非递归实现*/
#include <iostream>
using namespace std;
//设定为非重复的递增整数列：循环方法
int BinarySearch(int array[],int value,int length)
{
if(array == NULL || length < 1)
return -1;
int lp = 0;
int rp = length -1;
while(rp > lp)
{
int mid = (lp + rp)/ 2;
if(array[mid] == value)
return mid;
if(array[mid] > value)
rp = mid -1;
else
lp = mid +1;
}
}
//递归方法
int binarySearch(const int array[],int value,int lp, int rp)
{
if(array == NULL||lp > rp)
return -1;
int mid = (lp + rp)/2;
if(array[mid] == value)
return mid;
else
{
if(array[mid] > value)
binarySearch(array,value,lp,mid-1);
else
binarySearch(array,value,mid+1,rp);
}
}
int main()
{
const int length = 10;
int a[length] = {1,2,3,4,5,6,7,8,9,100};
cout <<"the loop result is: "<<BinarySearch(a,100,length)<<endl;
cout <<"the recursion result is: "<<binarySearch(a,100,0,length-1)<<endl;
system("PAUSE");
return 0;
}