How to use multiple inheritance for implementing different comparison logic? - c++

Question

I am trying to use interface IComparable (not in this mockup code) and its 2 implementations to work on same object.
I must use operators to do so.
I would like to do it without resolving like here c.right::operator--().
Here I have interfaces Common and Uni both inherited by Inter. Then I have right and left that blend into custom class implementing both Common and 2 versions of Uni interfaces.
2 different versions meaning one that uses operator to call f() and the other to call g().
#include<iostream>
class Common {
public:
Common() { std::cout << "common\n"; }
};
class Uni {
public:
Uni() { std::cout << "uni\n"; }
virtual void operator--() = 0;
};
class Inter : virtual public Common, public Uni {
public:
Inter() { std::cout << "inter\n"; }
};
class left : public Inter {
public:
left() { std::cout << "left\n"; }
void operator--() override { f(); }
virtual void f() = 0;
};
class right : public Inter {
public:
right() { std::cout << "right\n"; }
void operator--() override { g(); }
virtual void g() = 0;
};
class custom : public right, public left {
public:
custom() { std::cout << "custom\n"; }
void f() override { std::cout << "lol\n"; }
void g() override { std::cout << "gfunc\n"; }
};
class custom2 : public right, public left {
public:
custom2() { std::cout << "custom2\n"; }
void f() override { std::cout << "lol2\n"; }
void g() override { std::cout << "gfunc2\n"; }
};
int main()
{
custom c;
custom2 c2;
c.left::operator--();
c.right::operator--();
c2.right::operator--();
}