查找一个有序数组中的一个元素——二分法

#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<stdlib.h>
int binary_search(int arr[], int sz,int key)
{
int left = 0;
int right = sz - 1;
while (left <= right)
{
int mid = left + (right - left) / 2;   //求平均数（防止溢出
if (arr[mid] < key)
{
left = mid + 1;
}
else if (arr[mid]>key)
{
right = mid - 1;
}
else
{
return mid;
}
}
}
int main()
{
int mid = 0;
int key = 14;
int arr[] = { 0, 2, 3, 4, 5, 6, 7, 8, 10, 14 };
int sz = sizeof(arr) / sizeof(arr[0]);
int ret = binary_search(arr, sz, key);
if (arr[ret] == key)
{
printf("找到了!下标是%d\n", ret);
}
else
{
printf("找不到\n");
}
system("pause");
return 0;
}