CODEWITHSUNDEEP
c++inheritance
NBcode
NBcode

Reputation: 159

C++: Is there a way to specify a generalized class that inherits from another?

class Vec
{
    double dim[];
public:
    Vec(void);
    ~Vec(void);
    virtual void Add(Vec vector) = 0;

};

I want to replace the Vec in Vec::Add() with "any class that inherits from Vec". Is there a way to do that?

Upvotes: 1

Views: 159

Answers (3)

Jerry Coffin
Jerry Coffin

Reputation: 490108

Change the parameter to a reference to const Vec:

virtual void Add(Vec const &vector) = 0;

A class (publicly) derived from Vec can be passed by reference to the base class.

Also, since you apparently plan to use Vec as a base class, you probably want to make its dtor virtual too. Otherwise, if you attempt to destroy an object of the derived type via a pointer or reference to the base, you'll get undefined behavior.

Upvotes: 5

Luchian Grigore
Luchian Grigore

Reputation: 258568

Yes, you pass a pointer or a reference to a Vec:

 class Vec
{
    double dim[];
public:
    Vec(void);
    ~Vec(void);
    virtual void Add(Vec* vector) = 0;

};

Conversion from a pointer to a class that derives from Vec to a Vec* is implicit.

If you pass by value, you run into object slicing and the behavior won't be what you expect.

Upvotes: 2

Nikola Smiljanić
Nikola Smiljanić

Reputation: 26873

Use const reference to Vec, or a pointer to Vec

class Vec
{
    double dim[];
public:
    virtual void Add(const Vec& vector) = 0;
};

Upvotes: 2

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