#include<stdio.h>int main()
{char arr[] = {1,2,3,4,5,6,7,8,9,10};int k = 7;//查找kint left = 0;int right = sizeof(arr) / sizeof(arr[0]);int mid = (left + right) / 2 ; //中间元素的下标while(left<=right){if（arr[mid] < k）{left = mid + 1;}else if(arr[mid] < k){right = mid - 1;}else{printf("找到了，下标 是：%d\n",mid);break;}}if(left>right)
{printf("找不到了\n");
}return 0;
}