c++ - 转发声明和删除

Question

我的老师让我做期末作业。我需要用 C++ 列出一些东西(不能使用 boost、STL 等)。我的 Stuff 类必须在 List 类之后定义。我试过的小样本:

#include <cstdlib>
#include <iostream>
#include <string>
using namespace std;

class Stuff;

class List
{
    private :

        Stuff *s;
        int n;

    public :

        List(int n)
        {
            this->n = n;
            s = new Stuff[n];
        }

        ~List()
        {
            delete[] s;
            s = NULL;
            n = 0;
        }

};

class Stuff
{
    private :

        string name;
        double price;

    public :

        Stuff(){}
};

int main(int argc, char **argv)
{
    return 0;
}

我知道，那:

"If the object being deleted has incomplete class type at the point of deletion and the complete class has a non-trivial destructor or a deallocation function, the behavior is undefined."

但是我该怎么做呢？有任何想法吗？请记住，我不能使用 boost、STL 等。并且 Stuff 类必须在 List 类之后定义。我只是不知道...

Answer 1

要使这段代码工作，您需要在定义List 类构造函数和析构函数之前定义Stuff。

所以:

class Stuff;

class List
{
    private :

        Stuff *s;
        int n;

    public :
        List(int n);
        ~List();

};

class Stuff
{
    private :

        string name;
        double price;

    public :

        Stuff(){}
};

List::~List()
{
    delete[] s;
    s = NULL;
    n = 0;
}
List::List(int n)
{
    this->n = n;
    s = new Stuff[n];
}