#include <iostream>
using namespace std;
class Set{
public:
//returns union of two sets
friend Set operator |(Set set1, Set set2){
//bla-bla-bla
return set1;
}
};
class Ring:public Set{
public:
Ring(){}
Ring(const Set& ){}
};
int main()
{
Ring r1, r2, r;
r = r1|r2;
}
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