P6.17 P55307 P0003. Friend numbers

#include <iostream>
using namespace std;

int friendOf(int n) {
    int nfriend=0;
    for (int i=1; i<n; i++) if (n%i==0) nfriend = nfriend + i;
    return nfriend;
}


bool areFriends(int n1, int n2) {
    if (friendOf(n1)==n2 && friendOf(n2)==n1 && n1!=n2) return true;
    else return false;
}



int main() {
    int n1,n2;
    bool first=true;
    while (cin>>n1) {
        cin>>n2;
        if (areFriends(n1,n2)) {
            if (not first) cout<<",";
            cout<<"("<<n1<<" "<<n2<<")";
            first=false;
        }
    }
    cout<<endl;
}