my.cpp

#include<iostream>
using namespace std;
typedef long long ll;
//不开longlong见祖宗!

int main(){
    freopen("test.in","r",stdin);
    freopen("test1.out","w",stdout);
		int n;
    cin>>n;
    cout<<n * (n + 1) / 2<<endl;
    return 0;
}

std.cpp

#include<iostream>
using namespace std;
typedef long long ll;
//不开longlong见祖宗!

int main(){
    freopen("test.in","r",stdin);
    freopen("test2.out","w",stdout);
		int n;
    ll sum = 0;
    cin>>n;
	  for(int i = 1; i <= n; ++i)sum += i;
  	cout<<sum<<endl;
    return 0;
}

data.cpp

#include<iostream>
using namespace std;

int main()
{
    freopen("test.in","w",stdout);
    srand(time(0));
    int a = rand() % 100000;
    cout<<a<<endl;
    return 0;
}

duipai.cpp

#include<cstdio>
#include<cstdlib>
#include<iostream>

int main()
{
    int tmp=0;
    for(int i=1;i<=10000;i++)
    {
        system("./data");
        system("./my");
        system("./std");

        // if(i/100>tmp) {printf("-- %d --\n",i);tmp=i/100;}
        if(system("diff test1.out test2.out"))
        {
            printf("wrong in --> %d \n",i);
            break;
        }
        printf("process %d is correct\n",i);
    }
    return 0;
}