c++ - 使用析构函数后，代码显示 "reference to Book::~Book()"错误

Question

我是 C++ 的学习者，我对构造函数和析构函数感兴趣。我编译了下面的代码，它返回了对 Book::~Book() 错误的 undefined reference 。但是当我注释掉析构函数时，它工作正常。我想我可以在使用析构函数后创建成员函数。我在这里做错了什么？为了更好地理解，我在下面编写了我的代码

class Book
{
private:
    int *pages;
    int *price;

public:
    Book()        //default constructor
    {
        pages = new int;
        price = new int;
        *pages = 300;
        *price = 8;
    };  

    void pre_destructor()
    {
        std::cout << "The pages:" << *pages;
        std::cout << "The price:" << *price;
    }

~Book();             //destructor

    void post_destructor()
    {
        std::cout << "The pages:" << *pages << "\n";
        std::cout << "The price:" << *price << "\n";
        delete pages;
        delete price;
    }
};

int main()
{
    using namespace std;
    Book book1;

    cout << "Before using destructors" << endl;
    cout << "---------------------------------"<< endl;

    book1.pre_destructor();

    cout << "After using destructors" << endl;
    cout << "---------------------------------";

    book1.post_destructor();

    return 0;
}  //destructor is called here

Answer 1

我已经缩短了一点。之前的 void pre_destructor() 毫无意义；最好放在 dtor(“析构函数”的缩写)本身中，post_destructor() 甚至可能有害。

#include <iostream>

class Book
{
private:
    int *pages;
    int *price;

public:
    Book() : pages(new int(300)), price(new int(8)) {}  

    ~Book() {
        std::cout << "The pages:" << *pages << "\n";
        std::cout << "The price:" << *price << "\n";
        delete price;
        delete pages;
    } 
};

int main()
{
    {
        Book book1;
    } //destructor is called here

    return 0;
}  

live在 Coliru 的