class Base{
public:
	int Base_public;
protected:
	int Base_protected;
private:
	int Base_private;
};
class Derived:public Base{
public:
	int Derived_public;
protected:
	int Derived_protected;
private:
	int Derived_private;
public:
	void Check();
	void Check(Base& vBase,Derived& vDerived);
};
void Derived::Check()
{
	//this 是Derived类型的,在this所属类作用域(Derived作用域)里
//,Derived本身定义的变量,无论什么访问标号都可以 Derived_private =5; //ok Derived_protected=5; //ok Derived_public = 5; //ok //Derived继承Base来的变量,可以访问Base中public和protected标号的成员变量 Base_public =5;//ok Base_protected =5;//ok //Base_private =5;//error //给每个变量前加上this指针,更方便理解 //类类型变量在所属类作用域里,变量中由所属类自身定义的成员变量可以任意访问 //所属类继承来的变量,只可以访问public和protected成员变量 //类类型变量在其他作用域里,只能访问public成员变量 } // void Derived::Check(Base &vBase,Derived &vDerivde) { //vBase是Base类型,在Derived类作用域里(非本身作用域),只能访问public标示的成员变量 //vBase.Base_private =5;//error //vBase.Base_protected =5;//error vBase.Base_public =5;//ok //vDerived是Derived类型,在Derived作用域里(本身作用域),所属类定义的变量,可任意访问 vDerivde.Derived_public =5;//ok vDerivde.Derived_protected =5;//ok vDerivde.Derived_private =5;//ok //所属类继承来的变量,只能访问public,protected //vDerivde.Base_private =5;//error vDerivde.Base_protected =5;//ok vDerivde.Base_public =5;//ok //private任何时候只能在本身作用域使用 }

  

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