Dạ C++ ạ giúp e vs

1

#include <iostream>
using namespace std;
int a,b;
int main()
{   freopen("ptsohoc.INP","r",stdin);
    freopen("ptsohoc.OUT","w",stdout);
    ios_base::sync_with_stdio(false);
    cin.tie();cout.tie();

    cin>>a>>b;
    cout<<a+b<<endl;
    cout<<a-b<<endl;
    cout<<a*b<<endl;
    cout<<a/b<<endl;
    cout<<a%b<<endl;
    return 0;
}

2

#include <iostream>
using namespace std;
int n;
int main()
{   freopen("haics.INP","r",stdin);
    freopen("haics.OUT","w",stdout);
    ios_base::sync_with_stdio(false);
    cin.tie();cout.tie();
    cin>>n;
    cout<<n/10<<endl;
    cout<<n%10<<endl;
    return 0;
}

3

#include <iostream>
using namespace std;
int n;
int main()
{   freopen("bacs.INP","r",stdin);
   freopen("bacs.OUT","w",stdout);
    ios_base::sync_with_stdio(false);
    cin.tie();cout.tie();
    cin>>n;
    cout<<n/100<<endl;
    cout<<n%100/10<<endl;
    cout<<n%10<<endl;
    return 0;
}