#include <iostream>

class Abc
{
private:
    static unsigned int ct;

public:
    void f1()
    {
        for (int i = 0; i < 5; ++i)
            f2();
    }

    void f2() {
        std::cout << Abc::ct << "\t";
        ++Abc::ct;
    }
};

unsigned int Abc::ct = 0;

int main()
{
    Abc obj;
    obj.f1();

    Abc obj2;
    obj2.f1();
}