派生类比基类有更多的方法 [英] More methods in derived classes than base class

问题描述

我想就这个派生类的编程风格提出一个问题：

I would like to ask a question about programming style in this case of derived class:

class A
{
public:
   virtual foo1()=0;
}

class B: public A
{
 public:
  virtual foo1();
  virtual foo2();
 }

class C: public A
{
 public:
  virtual foo1();
 }

int main() {
 B mB();
 C mC();
 mB.foo2() //OK!
 mC.foo2() // obviously, it is not correct
return 0;}

$ b b

因此，一个派生类是否应该有比抽象基类少或相等的公共方法？

Therefore, should a derived class have less or equal public methods than the abstract base class?

如果派生类需要更多方法，应该是私有的吗？

If the derived classes require more methods, should these be private?

推荐答案

这个类结构没有问题。一个派生类有比父类更多的方法没有错误 - 这是很常见的。 mC.foo2（）; 行错了，这不是类的错误。

There is nothing wrong with this class structure. There is nothing wrong with a derived class having more methods than the parent class-- it's quite commonplace. The line mC.foo2(); is just wrong, and that is not the fault of the classes.

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