类与类的指针

parent.h

#pragma once
#include <iostream>

class Parent
{
public:
	Parent();
	~Parent();
	char * str;
	void print();
	void parentMehtod();

};

parent.cpp

#include "parent.h"


Parent::Parent()
{
	this->str = "this is Parent";
	std::cout << "Parent create" << std::endl;
}


Parent::~Parent()
{
	std::cout << "fu delete" << std::endl;

}

void Parent::print()
{
	std::cout << this->str << std::endl;
}

void Parent::parentMehtod()
{
	std::cout << "Parent method" << std::endl;
}

child.h

#pragma once
#include "parent.h"
class Child:public Parent
{
public:
	Child();
	~Child();
	char *strzi;
	void print();
	void childMethod();

};

child.cpp

#include "child.h"


Child::Child()
{
	this->strzi = "this is child";
	std::cout << "Child create" << std::endl;
}


Child::~Child()
{
	std::cout << "Child delete" << std::endl;
}

void Child::print()
{
	std::cout << this->strzi << std::endl;

}
void Child::childMethod()
{
	//std::cout << this->strzi << std::endl;
	std::cout << "childMethod" << std::endl;
}

#include <iostream>

#include"parent.h"
#include "child.h"

//类而言，数据是私有的，代码是共享
//空指针可以调用方法，涉及内部成员会崩溃 (main4)

/*
	1.父类指针引用父类对象，完全正常引用(main1)
	2.子类指针引用子类对象，覆盖父类的同名函数(main1)
	3.父类指针引用子类对象，只能引用父类中的函数(main2)
	4.子类指针引用父类对象，子类不涉及内部数据的函数会调用成功;涉及到内部数据的会调用成功，执行失败; (main3)
	子类指针可以引用父类的不重名的函数;子类指针无法引用父类的同名方法,因为子类会覆盖父类的方法，
	想要执行父类的方法：pChild->Parent::print();
*/


void main4()
{
	Child *pChild(nullptr);
	pChild->childMethod();

	std::cin.get();


}
void main3()
{
	Parent *pParent = new Parent;
	Child *pChild = static_cast<Child *>(pParent);
	pChild->parentMehtod();
	//pChild->print();
	pChild->Parent::print();

	//std::cout << pChild->strzi << std::endl;


}
void main2()
{
	Parent *pParent = new Child();
	pParent->print();
	pParent->parentMehtod();
}

void main1()
{
	Parent *pParent = new Parent;
	pParent->print();
	pParent->parentMehtod();

	Child *pChild = new Child;
	pChild->print();
	pChild->childMethod();
	pChild->parentMehtod();

}