在程序里，有些私有属性 也想让类外函数或者类进行访问，就需要用到友元的技术

  • 友元的目的就是让一个函数或者类 访问另一个类中私有成员

友元关键字为 friend

代码示例

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#include<iostream>
using namespace std;

//建筑物类
class Building {

	friend void goodGay(Building* building);//全局函数是 Builiding 好朋友，可以访问私有成员
public:
	Building() {
		m_BedRoom = "卧室";
		m_SittingRoom = "客厅";
	}

public:
	string m_SittingRoom;

private:
	string m_BedRoom;
};


void goodGay(Building *building) {
	cout << "好基友正在访问 " << building->m_SittingRoom << endl;
	cout << "好基友正在访问 " << building->m_BedRoom << endl;
}

int main() {
	Building building;
	goodGay(&building);
	return 0;
}