折半查找

// 折半查找.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include<iostream>
using namespace std;
int binarySearch(int a[],int length,int k)
{
int left=0;int right=length-1;
int count = 0;
while(left<=right)
{
count=count+1;
int index=left+(right-left)/2;
if(a[index]>k)
right=index-1;
else if(a[index]<k)
left=index+1;
else
return k;
}
return -1;
}

int main()
{
int a[]={1,2,3,4,5,6,7,8,9,10,11,12,14};
int k=4;
cout<<binarySearch(a,13,k);
system("pause");
return 0;
}