折半查找的实现

//折半查找的方法
#include<stdio.h>
#include<stdlib.h>
int bin_search(int ch, int arr[], int len)
{
int left=0;
int right=len-1;
int mid;
while (left <= right)
{
mid = (left + right) >> 1;
//mid=((right-left)>>1)+left;
//mid=(right&left)+((left^right)>>1)
if (arr[mid] < ch)
{
left = mid + 1;
}
else if (arr[mid] > ch)
{
right = mid - 1;
}
else
return mid;
}
return 0;
}
int main()
{
int ret;
int num;
scanf("%d", &num);
int arr[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
ret = bin_search(num, arr, sizeof(arr) / sizeof(arr[0]));
printf("%d", ret);
system("pause");
return 0;
}