覆盖纯虚函数的参数数量 [英] Override number of parameters of pure virtual functions

问题描述

我已经实现了以下接口:

I have implemented the following interface:

template <typename T>
class Variable
{
public:
  Variable (T v) : m_value (v) {}
  virtual void Callback () = 0;
private:
  T m_value;
};

一个合适的派生类可以这样定义:

A proper derived class would be defined like this:

class Derived : public Variable<int>
{
public:
  Derived (int v) : Variable<int> (v) {}
  void Callback () {}
};

但是，我想派生 Callback 接受不同参数的类(例如:void Callback (int a, int b)).有办法吗?

However, I would like to derive classes where Callback accepts different parameters (eg: void Callback (int a, int b)). Is there a way to do it?

推荐答案

这个问题我遇到过很多次了.

This is a problem I ran in a number of times.

这是不可能的，并且有充分的理由，但有一些方法可以实现基本相同的目标.就个人而言，我现在使用:

This is impossible, and for good reasons, but there are ways to achieve essentially the same thing. Personally, I now use:

struct Base
{
  virtual void execute() = 0;
  virtual ~Base {}
};

class Derived: public Base
{
public:
  Derived(int a, int b): mA(a), mB(b), mR(0) {}

  int getResult() const { return mR; }

  virtual void execute() { mR = mA + mB; }

private:
  int mA, mB, mR;
};

在行动:

int main(int argc, char* argv[])
{
  std::unique_ptr<Base> derived(new Derived(1,2));
  derived->execute();
  return 0;
} // main

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