Untitled

How to give a class as valid parameter for printf where it returns as a string?
printf("blah blah  %s  ", customclass);

class CustomClass
{
public:
    int x;
    int y;
};

ostream &operator<<(ostream &os, CustomClass c)
{
    os << "{" << c.x << "," << c.y << "}";
    return os;
}

...

CustomClass customclass;
customclass.x = 5;
customclass.y = 7;
std::cout << customclass << "n";

cout << "blah blah " << typeid(customclassobject OR customclass).name() << endl;