友元类的应用"/>
友元类的应用
要求
人物
基类:class Lovers
子类:Boyfriend,Girlfriend
第三者:class Others
子类:(无)
故事是这样的
基类Lovers的name属性访问级别为protected,但将Others类设为友缘关系。
第三者Others类到自己拥有kiss方法,希望调用。此kiss方法传参为Boyfriend类型的的对象。
代码
#include<iostream>
#include<string>
//基类
class Lovers
{
public:Lovers(std::string lovers_name);//构造器
protected:std::string name;friend class Others;
};
//子类
class Boyfriend :public Lovers
{
public:Boyfriend(std::string name);
};
class Girlfriend :public Lovers
{
public:Girlfriend(std::string name);
};
//第三者
class Others
{
public:std::string name;Others(std::string name);//构造器void dosomething(Boyfriend duixiangname);
};
//基类构造器
Lovers::Lovers(std::string lovers_name)
{this->name = lovers_name;
}
//子类构造器
Boyfriend::Boyfriend(std::string name) :Lovers(name)
{this->name = name;
}
Girlfriend::Girlfriend(std::string name) : Lovers(name)
{this->name = name;
}
//第三者构造器
Others::Others(std::string name)
{this->name = name;
}
//子类方法(访问基类的private部分)
void Others::dosomething(Boyfriend duixiangname)//传入的是一个class对象
{std::cout << "I am kissing " << duixiangname.name << std::endl;
}
int main()
{Boyfriend person1("Tony");Girlfriend person2("Alice");Others person3("Uncle");person3.dosomething(person1);system("pause");
}
运行结果
第三者Others成功运用自己的kiss方法访问到了Lovers类的name成员
输出:
I am kissing Tony
请按任意键继续. . .
版本2
将29,51行的参数类型Boyfriend改成了Lovers,这样在60行的调用不受限制
#include<iostream>
#include<string>
//基类
class Lovers
{
public:Lovers(std::string lovers_name);//构造器
protected:std::string name;friend class Others;
};
//子类
class Boyfriend :public Lovers
{
public:Boyfriend(std::string name);
};
class Girlfriend :public Lovers
{
public:Girlfriend(std::string name);
};
//第三者
class Others
{
public:std::string name;Others(std::string name);//构造器void dosomething(Lovers duixiangname);
};
//基类构造器
Lovers::Lovers(std::string lovers_name)
{this->name = lovers_name;
}
//子类构造器
Boyfriend::Boyfriend(std::string name) :Lovers(name)
{this->name = name;
}
Girlfriend::Girlfriend(std::string name) : Lovers(name)
{this->name = name;
}
//第三者构造器
Others::Others(std::string name)
{this->name = name;
}
//子类方法(访问基类的private部分)
void Others::dosomething(Lovers duixiangname)//传入的是一个class对象
{std::cout << "I am kissing " << duixiangname.name << std::endl;
}
int main()
{Boyfriend person1("Tony");Girlfriend person2("Alice");Others person3("Uncle");person3.dosomething(person2);system("pause");
}
输出:
I am kissing Alice
请按任意键继续. . .
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