public private protected三种标号

#include<iostream>#include<string>//#include<vector>using namespace std;class Base{public:int j;int basemem( Base &b){k = 1; //使用了k//k =b.k; error C2248: 'Base::k' : cannot access private member declared in class 'Base' 同样不行。return 0;};int basemem(){return k;};void setk(){k=1;}protected:int i;private:int k;};class pub_Base : public Base{public:void pub( pub_Base &d,const Base &b){// k =1; //因为它在派生类中无法调用了 i = 1;d.i = 1;cout << d.i << endl;i = d.i;//b.i = 1;}int fun(){this->setk();//k = 1;cout << basemem()<<endl;return 0;}int pub_i;};class pubb_Base : public pub_Base{public:int pubb_i;void pubbb(const pub_Base &d,const Base &b){i = 1;//i = d.i;//因为d.i不在pub_base 中了//b.i = 1;}};void fun1(pub_Base &d){//d.i; 通常 cout << "fun1 是"<<endl;}int main(){ int test = 0; Base b = Base(); Base b1 = Base(); pub_Base pb = pub_Base(); pub_Base pb1 = pub_Base(); pb.fun(); // pb.i; //protected 可以被调用，但是仅仅局限于在成员内部 b.basemem(b1); pubb_Base pbb = pubb_Base(); pb.pub(pb1,b); //pbb. test = b.basemem(); //pb.i; //b.i; // error ; i 是protected 成员不能运行。 b.j = 3; pb.pub_i = 3; pb.j; //pb.i; //protected 可以被调用，但是仅仅局限于在成员内部 //pb.k; //b.k; // error; k 是private成员不能远行}

 

测试了public private protected三种标号使用情况；

 

派生类中的基类的private成员不能直接被访问；

派生类中的基类的protected 可以在派生类中访问；