#include<iostream>
using namespace std;
/*
2分查找法
优点：查找速度快，平均性能好。
缺点：待查表为有序表 
*/
int main()
{
int binSearch(const int*,int,int); 
int arr[10] = {0,1,2,3,4,5,6,7,8,9};
cout << binSearch(arr,9,5) << endl;
 
return 0;
} 


int binSearch(const int* Array,int start,int end,int key)
{
int left,right;
int mid;
left = start;
right = end;
//注释中为递归算法，履行效力低，不推荐
/* 
if(key < Array[mid])
{
return(binSearch(Array,left,mid⑴,key));
}
else if(key > Array[mid])
{
return(binSearch(Array,mid+1,right,key));
}
else
return mid;
*/


while(left<=right)
{
mid = (left+right)/2;
if(key==Array[mid])
{
return mid;
}
else if(key<Array[mid])
{
right=mid⑴;
}
else if(key>Array[mid])
{
left=mid+1;
}
}
return ⑴;
}