Thread: Abstract inheritence

It's not a problem if that's what you want. You may want a sub-interface that also cannot be instantiated.

Code:

class Bird {
public:
    virtual ~Bird() {}
    virtual void sing() = 0;
    virtual void eat() = 0;
    virtual void walk() = 0;
};

class FlyingBird : public Bird {
public:
    virtual void fly() = 0;
};