利用函数bin

#define _CRT_SECURE_NO_WARNINGS 1 #include<stdio.h> #include<stdlib.h> int bin_search(int arr[],int key,int left,int right) { while(left<=right) { int mid = left-(left-right)/2; if(arr[mid]>key) { right = mid - 1; } else if(arr[mid]<key) { left = mid = 1; } else { return mid; } return -1; //因为0是下标，因此返回值可设定为-1，下标中无-1 int main() { int arr[] = {1,2,3,4,5,6,7,8,9} int ret =bin_search(arr,5,3,8)//意为在5与8之间寻找3 if（ret == -1） printf("no\n"); else { printf("%d\n",ret); } system ("pause\n); return 0;//此题输出结果为no }