编写一个函数，返回整型数组中的第二大值

#include <iostream>using namespace std;int func(const int a[], int len){if (a == NULL)return -1;if (len < 2){cout<<"数组长度小于2, 无需比较"<<endl;return a[0];}int max = a[0];int second = a[0];for (int i=1; i<len; i++){if (a[i] > max)// 更新最大值和第二大值{second = max;max = a[i];}else if (a[i]>second && a[i]<max){second = a[i];// 更新第二大值} }return second;}int main(int argc, char *argv[]){int num[] = {1, 2, 3, 5, 9, 8};int len = sizeof(num)/sizeof(num[0]);int ret = func(num, len);if (ret != -1){cout<<"Second = "<<ret<<endl;}return 0;}

结果：

second = 8