C++之继承

#include <iostream>

using namespace std ; 

class  Animal
{
	private:
		int age ;

	protected:
		int id ; 

	public:
		int Height ;
		void Say_hi(void)
		{
			cout << "this is hello" <<endl ;
		}
};

//无论哪种继承，父类私有成员在子类不可访问
//公有继承,父类的公有跟受保护权限到了子类权限不变
//受保护继承,父类的公有成员变成子类的受保护成员，受保护成员权限不变
//私有继承,父类的公有成员及父类的受保护成员变成子类的私有成员

class People : public  Animal
{
	private:
		int aa ; 	

	protected:
	int cc ; 

	public :
	int a ; 

	void Say_hi(void)
	{
		cout << "hi " << endl ;
	}

	void Say_cc(void)
	{
		cout << "cc : " << cc << endl ;
		cout << "id : " << id << endl ;
		//cout << "age : " << age << endl ;
		cout << "aa : " << aa << endl ;
	}
};

int main(void)
{

	People  pp ;
//	pp.Height = 100 ;
//	pp.Say_cc();
//	pp.cc = 200 ;    //受保护的变量不允许直接访问
//	pp.id = 200 ;
//	pp.Say_hi();

	pp.Say_hi();
	//两者皆可
	pp.Animal::Say_hi();
	pp.People::Say_hi();

	return 0 ;
}

运行结果：