#include <iostream>
    #include <sstream>
    #include <string>

    using namespace std;

    class MyTypeA
    {
    public:
        MyTypeA(int i) : _i(i) {};
        virtual ~MyTypeA() {};

        string getStr() const { return to_string(_i); }

    private:
        int _i;
    };

    class MyTypeB
    {
    public:
        MyTypeB(int i) : _i(i) {};
        virtual ~MyTypeB() {};

        string getStr() const { return to_string(_i); }

    private:
        int _i;
    };

    class Message : public ostringstream
    {
    public:
        Message() {};
        virtual ~Message() {};
    };

    ostream& operator <<(ostream &os, const MyTypeA &a) {
        return os << a.getStr();
    };

    ostream& operator <<(ostream &os, const MyTypeB &b) {
        return os << b.getStr();
    };

    int main()
    {
        MyTypeA a(10);
        MyTypeA b(-10);

        Message m;
        m << a << "-" << b; // This works just fine!
        m << a << "-" << b << endl; // Ba dumm tss

        return 0;
    }