条款06: 若不想使用编译器自动生成的函数，就该明确拒绝-编程知识

条款06: 若不想使用编译器自动生成的函数，就该明确拒绝

news/2025/1/15 18:28:55/文章来源:https://www.cnblogs.com/BoYuCG/p/18405680

1. 将Copy构造函数或copy Assignment操作符声明为private
2. 因为member函数和friend函数可以调用private函数，不去定义private函数，当调用时会获得一个链接错误

class HomeForSale00
{
public:HomeForSale00() {}void GenerateHomeForSale00Member(){HomeForSale00 home00;HomeForSale00 home01;//HomeForSale00 home02(home00); //链接错误//home00 = home01; //链接错误
    }
private:friend void GenerateHomeForSale00Friend();HomeForSale00(const HomeForSale00&);HomeForSale00& operator=(const HomeForSale00&);
private:uint32_t HomePrice;
};void GenerateHomeForSale00Friend()
{HomeForSale00 home00;HomeForSale00 home01;home00.HomePrice = 200;//HomeForSale00 home02(home00); //链接错误//home00 = home01; //链接错误
}void Test00()
{HomeForSale00 home00;HomeForSale00 home01;//HomeForSale00 home02(home00); //private不可访问//home00 = home01; //private 不可访问
GenerateHomeForSale00Friend();home00.GenerateHomeForSale00Member();
}

1. 为了阻止copying动作设计Uncopyable的base class
2. 因为Uncopyable class不含数据，因此不一定得以public继承，以及Uncopyable class的析构函数为虚函数

class Uncopyable
{
protected:Uncopyable() = default;~Uncopyable() = default;
private:Uncopyable(const Uncopyable&) = delete;Uncopyable& operator=(const Uncopyable&) = delete;
};class HomeForSale01:private Uncopyable
{
public:HomeForSale01() {}void GenerateHomeForSale01Member(){HomeForSale01 home00;HomeForSale01 home01;//HomeForSale01 home02(home00); //链接错误//home00 = home01; //链接错误
    }
private:friend void GenerateHomeForSale01Friend();HomeForSale01(const HomeForSale01&);HomeForSale01& operator=(const HomeForSale01&);
private:uint32_t HomePrice;
};void GenerateHomeForSale01Friend()
{HomeForSale01 home00;HomeForSale01 home01;home00.HomePrice = 200;//HomeForSale01 home02(home00); //链接错误//home00 = home01; //链接错误
}void Test01()
{HomeForSale01 home00;HomeForSale01 home01;//HomeForSale01 home02(home00); //private不可访问//home00 = home01; //private 不可访问
GenerateHomeForSale01Friend();home00.GenerateHomeForSale01Member();
}int main()
{Test00();Test01();return EXIT_SUCCESS;
}