2020-05-30

/*
虚函数表达：virtual <类型><函数名>(<参数表>);
*/
#include<iostream>
using namespace std;
// 基类 base
class Base{
public:
     //虚函数
    virtual void display() {
        cout<<"Base::display()\n";
    }
  //纯虚函数
  virtual void hide()=0;
}; 

/*
虚函数表达：virtual <类型><函数名>(<参数表>);
*/
#include<iostream>
using namespace std;
class Base {
    public:
    int base_i;
    virtual void display(){
        cout<<"Base:display\n";
    }
//纯虚函数
 virtual void pureFunc()=0;
void nomalFunc();
};
class Derived:public Base{
    public:
int derived_j;
    void display(){
        cout<<"Derived:display\n";
    }
};
int main(){
    Base *ptr = new Derived();
    ptr->display();
}

Derived d;
d.Base1::a=3;
d.Base1::display();

class Base{xxx};
class Base1:virtual Base{xxx}
class Base2:virtual Base{xxx}
class Derived:public Base1,public Base2{xxx}

//test02
#include <iostream>

using namespace std;

class MyTestB{
public:
    MyTestB(){};
};
class MyTestA{
public:
    MyTestB b;
};
int main(int argc)
{
    MyTestA a;
    cout<<"hello";
    return 0;
}

class MyTestB{
public:
    MyTestB(){};
};
class MyTestA:public MyTestB{};
int main(int argc)
{
    MyTestA a;
    cout<<"hello";
    return 0;
}

#include <iostream>

using namespace std;

class MyTestA{
public:
    virtual void DisPlay();
};
int main(int argc)
{
    MyTestA a;
    cout<<"hello";
    return 0;
}

#include <iostream>

using namespace std;
class MyTestD{};
class MyTestC:virtual public MyTestD{};
class MyTestB:virtual public MyTestD{};

class MyTestA:public MyTestC,public MyTestB{};

int main(int argc)
{
    MyTestA a;
    cout<<"hello";
    return 0;
}