如果一个类有一个非纯析构函数，它还能是纯抽象的吗? [英] Can a class still be pure abstract if it has a non-pure destructor?

问题描述

我正在做一个练习，该练习要求我选取一个 Rodent 基类并使其成为一个纯抽象类.我对纯抽象类的理解是它充当接口并且只包含纯虚函数.虽然这是一个简单的练习，但我对本书提供的解决方案有疑问:

I am working on an exercise which asks me to take a base class Rodent and make it a pure abstract class. My understanding of a pure abstract class is that it acts as an interface and only contains pure virtual functions. Although this is an easy exercise I have a problem with the solution provided by the book:

class Rodent
{
    public:

    virtual ~Rodent() {cout << "Destroy rodent" << endl;}
    virtual void run() = 0;
    virtual void squeak() = 0;
};

如您所见，作者为析构函数添加了一个虚拟定义.加入这个定义是不是意味着这是一个抽象类而不是一个纯"的抽象类?

As you can see the author has added a dummy definition for the destructor. Does the adding of this definition not mean that this is an abstract class and not a 'pure' abstract class?

推荐答案

一个抽象类必须包含至少一个纯虚函数.

An Abstract class must contain atleast one pure virtual function.

你的类已经有两个纯虚函数run()和squeak()，所以你的类是抽象的，因为这两个纯虚函数.

Your class already has two pure virtual functions run() and squeak(), So your class is Abstract because of these two pure virtual functions.

您不能创建此类的任何对象.

You cannot create any objects of this class.

纯抽象类，是专门具有纯虚函数(没有数据)的类.由于您的析构函数不是纯虚拟的，因此您的类不是纯抽象类.

A pure abstract class, is a class that exclusively has pure virtual functions (and no data). Since your destructor is not pure virtual your class is not Pure Abstract Class.

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