5 Object as function argument

#include <iostream>
using namespace std;
class num{
    public:
    int a;
    void getdata(){
        cout<<"Enter number ";
        cin>>a;
    }
    void display(){
        cout<<a;
    }
    void sum(num  x, num y);
};
void num::sum(num x , num y){
    a = x.a + y.a;
}
int main()
{
    num f,s,ans;
    f.getdata();
    s.getdata();
    ans.sum(f,s);
    cout<<"sum is ";
    ans.display();
    return 0;
}
/*
Output
Enter number 5
Enter number 5
sum is 10
*/