父类指针和子类指针的步长

#define  _CRT_SECURE_NO_WARNINGS 
#include <iostream>

using namespace std;

class Parent
{
public:
	Parent(int a)
	{
		this->a = a;
	}

	virtual void print()
	{
		cout << "Parent::print() " << a << endl;
	}
protected:
	int a;
};

class Child :public Parent{
public:
	Child(int a) :Parent(a)
	{

	}

	virtual void print()
	{
		cout << "Child :: Print() " << a <<endl;
	}
private:
	int b;
};

int main(void)
{
	Child array[] = {Child(0), Child(1), Child(2) };
	//						array[0]   array[1] array[2]

	Child *cp = &array[0];
	Parent *pp = &array[0];


	cp->print(); //Child::
	pp->print(); //Child::发生多态

	cout << "------" << endl;

	cp++; //Child::12
	//pp++;//8
	pp = cp;

	cp->print();
	pp->print();

	cout << " -----  " << endl;

	
	int i = 0;
	for (i = 0, cp = &array[0], pp = cp; i < 3; i++, cp++, pp =cp) {
		pp->print();
	}
	
	return 0;
}

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>


using namespace std;


class Fu
{
public:
	Fu();
	Fu(int ta): a(ta) {};
	~Fu();
	virtual void print() { cout << "Fu a = "<< a << endl; }
private:
	int a;
};

class Zi : public Fu
{
public:
	Zi();
	Zi(int a, int tb) :Fu(a) ,b(tb){};
	virtual void print() { cout << "Zi b = " << b << endl; }
	~Zi();
	
private:
	int b;
};

Zi::Zi()
{
}

Zi::~Zi()
{
}

Fu::Fu()
{
}

Fu::~Fu()
{
}

int main(char *argv[], int argc)
{
	Zi zi[] = { Zi(100,200),Zi(300,400),Zi(500,600) };

	Fu * pFu = zi;
	/*
	会崩溃,因为(pFu + i) == (pFu + sizeof Fu) 而不是(pFu + sizeof Zi)

	for (int i = 0; i < 3; i++)
	{
		(pFu + i)->print();
	}
	*/

	//解决方法
	Zi * zi1[] = { new Zi(1,2),new Zi(3,4), new Zi(5,6), new Zi(7,8) };
	
	for (int i = 0; i < sizeof(zi1) / sizeof(Zi *); i++)
	{
		pFu = zi1[i];
		pFu->print();
	}
	return 0;
}