CODEWITHSUNDEEP
classpointersmethodsmember
JonnyRobbie
JonnyRobbie

Reputation: 614

Pointer to a child class method

So here's my code I'm working with:

#include <iostream>

class Node
{
public:
    void speak(){std::cout << "I'm a base node" << std::endl;}
};

class Child : public Node
{
public:
    void speak(){std::cout << "I'm a child node" << std::endl;}
};

int main()
{
    Node node;
    Child child;

    node.speak();
    child.speak();

    std::cout << "= Pointers..." << std::endl;
    Node* pnode = &node;
    Node* pchild = &child;

    pnode->speak();
    pchild->speak();
}

And here's the output:

I'm a base node
I'm a child node
= Pointers...
I'm a base node
I'm a base node

The pchild->speak(); calls the Node's method and not the Child's one.

Now my problem is that I may have many different types of nodes, with varying number of connections. Thus I cannot declare a member pointer with a ChildX class, but only with a generic Node class. But each node will have a certain method that I want called.

I've tried to have a pointer to that method itself instead of to the class (since it would always be int (*foo)() type), but the compiler complains about invalid use of non-static member function.

So both of my approaches don't work. Neither pointer to a class, nor pointer to classes member function.

Upvotes: 0

Views: 34

Answers (1)

kabanus
kabanus

Reputation: 25895

Familiarize yourself with virtual functions and polymorphism - both key concepts in c++.

In your question you simply need to define

virtual void speak(){std::cout << "I'm a base/child node" << std::endl;}

Upvotes: 1

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