C++继承问题（白兰花例）

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C++中有三种类的访问限定符，同样在运用继承这个知识的时候，也有三种继承方式，public，private，protected：

如图：

1.公有继承

这种情况下，基类成员的公有成员和保护成员在被派生类继承的时候，他们的性质不变，可被派生类对象访问，但是私有成员，不可被访问。

2.私有继承

基类成员都不可被派生类对象访问。

3.保护继承

基类的公有成员函数和保护成员函数在派生类中都是保护成员函数，只能被派生类的成员函数或者由友员访问。

代码：例子：

#include <iostream>#include <string>using namespace std;class Botany{public://构造函数（Botany）Botany(char* name = ""):_name(name){cout << "Botany()" << endl;}Botany(const Botany& s):_name(s._name){//cout << "Botany(const Botany& s)" << endl;}Botany& operator=(const Botany& s){if (this != &s){_name = s._name;}return *this;}~Botany(){}virtual void Display(){cout << "Botany::" << _name << endl;}protected:string _name;};class Tree :virtual public Botany     //{public:Tree(char* name, int hight = 0):Botany(name)             //继承基类时 写法, _hight(hight){//cout << "Tree()" << endl;//测试需要}Tree(const Tree& s): Botany(s), _hight(s._hight){//cout << "Tree(const Tree& s)" << endl;}Tree& operator=(const Tree& s){if (this != &s){Botany::operator=(s);_hight = s._hight;}return *this;}~Tree(){}void Display(){cout << "Tree::" << _hight << endl;}protected:int _hight;};//FLOWERclass Flower :virtual public Botany{public:Flower(char * name, int colour): Botany(name), _colour(colour){//cout << "Flower()" << endl;}Flower(const Flower& s): Botany(s), _colour(s._colour){//cout << "Flower(const Flower& s)" << endl;}Flower& operator=(const Flower& s){if (this != &s){Botany::operator=(s);_colour = s._colour;}return *this;}~Flower(){}void Display(){cout << "Flower::" << _colour << endl;}protected:int _colour;};// 白兰花，即是树又是花。class MicheliaAlba : public Flower, public Tree    {public:MicheliaAlba(char* name, int hight, int colour):Botany(name), Flower(name, colour), Tree(name, hight){}MicheliaAlba(const MicheliaAlba& s): Botany(s), Flower(s), Tree(s){}MicheliaAlba& operator=(const MicheliaAlba& s){if (this != &s){Botany::operator=(s);Flower::operator=(s);Tree::operator=(s);}return *this;}~MicheliaAlba(){}void Display(){cout << " MicheliaAlba::" << _name << "-" << _colour << "-" << _hight << endl;}};void Test1(){Botany l1("兰花");Flower l2("兰花", 1);Tree l3("兰花", 2);//Botany *p1 = &l1;//Botany& p2 = l2;//虚函数 代表测试//Botany *p2 = &l3;l1.Display();l2.Display();MicheliaAlba s1("兰花", 1, 10);s1.Display();}int main(){Test1();getchar();return 0;}

基类成员

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