Question

I want to implement a behavior I saw in an engine (Unity3D) in a C++ project.

The following code is in C# (Unity’s language):

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {

    void Update() {
        //Update is called every frame
    }
}

Since I don’t have access to MonoBehavior source I can only guess that Update() is a virtual function that can be implemented like this.

I want to replicate the same behavior in C++. Have a loop in main() and a super object will have it’s Update() method called in that loop and all it’s children should inherit this super object and have the possibility to implement Update() and use it.

I know it’s an ambiguous question but I’ve searched everywhere for an answer and didn’t found one.

Here is an example:

class Base
{
 public:
     virtual void Update();
};

class Object: public Base
{
 public:
     void Update();
};

void main()
{
     Base* base;
     while(1)
     {
        base->Update();
     }
}

And the result should be that Object’s Update() should be called through Base. I am 100% the code above doesn’t work and that is why I am in need of some ideas.

Answer 1

C++ does not have interfaces. You create an abstract class with a pure virtual method.

class MonoBehaviour 
{
    virtual void Update() = 0;
};

class your_class : MonoBehaviour 
{
    void Update() 
    { 
        // implement here. 
    }
};