#include<iostream>
#include<string>
using namespace std;
void main()
{
const int n=3;
double arr[n];
double m=0;
for(int i=0;i<n;i++)
{
cout<<"输入第"<<i+1<<"次40米跑的成绩(秒):";
cin>>arr[i];
m=m+arr[i];
}
m=m/n;
cout<<"总共跑了"<<n<<"次\n";
cout<<"平均成绩为"<<m<<"秒\n";
}