c++继承

#include <iostream>
#include <typeinfo>

// definitation of Graph
class Graph
{
public:
   virtual void draw() { std::cout << "Graph::draw() : just as an interface\n"; }
};


// definition of Rectangle, derived from Graph
class Rectangle : public Graph
{
public:
    void draw() { std::cout << "Rectangle::draw(): programs of draw a rectangle\n"; }
};


// definition of Circle, derived from Graph
class Circle : public Graph
{
public:
    void draw() { std::cout << "Circle::draw(): programs of draw a circle\n"; }
};


// definitaion of fun(): as a call interface
void fun(Graph* ptr)
{
    std::cout << "pointer type: " << typeid(ptr).name() << "\n";
    std::cout << "RTTI type: " << typeid(*ptr).name() << "\n";
    ptr->draw();
}

// test 
int main()
{
    Graph g1;
    Rectangle r1;
    Circle c1;

    // call by object name
    g1.draw();
    r1.draw();
    c1.draw();

    std::cout << "\n";

    // call by object name, and using the scope resolution operator::
    r1.Graph::draw();
    c1.Graph::draw();

    std::cout << "\n";

    // call by pointer to Base class
    fun(&g1);
    fun(&r1);
    fun(&c1);
    return 0;
}
//本实验通过加virtual关键字可使基类指针调用派生类成员

// 总结：1、同名覆盖原则：外有内无外有效 。   内有外有（即使只是函数名相同，重载的也包括其中）内有效。   若几个基类有同名成员，则派生类将绝杀。
//       2、二元作用域运算符 通过:: 可以访问被隐藏的父级成员，形式：对象名.基类::    ptr->基类::
//       3、类型兼容：子转父，子初父&，子p*隐含转父p*  attention:兼容后只能使用从基类继承来的成员

 

 

 

 

 

#ifndef _BATTERY_HPP
#define _BATTERY_HPP
class Battery {
private:
    int capacity;
public:
    Battery(int cp=70):capacity(cp){}
    int get_capacity()const { return capacity; }
};
#endif

#ifndef _CAR_HPP
#define _CAR_HPP
#include<iostream>
#include<string>
#include<iomanip>
using namespace std;
class Car {
private:
    string maker,model;
    int year, odometers;

public:
    Car(string maker,string model,int y,int od=0):maker(maker),model(model),year(y),odometers(od){}
    void info()const;
    void update_odometers(int od);
};

void Car::info()const {
    cout << left << setw(15) << "maker:" << maker << endl
        << setw(15) << "model:" << model << endl
        << setw(15) << "year:" << year << endl
        << setw(15) << "odometers:" << odometers << endl;
}

void Car::update_odometers(int od) {
    if (od < 0)cout << "wrong odometers" << endl;
    else odometers = od;
}
#endif // !_CAR_HPP

#ifndef _ELECTRICCAR_HPP
#define _ELECTRICCAR_HPP
//#include<string>
#include"Car.hpp"
#include"Battery.hpp"
class ElectricCar :public Car{
private:
    Battery battery;
    
public:
    ElectricCar(std::string maker, std::string model, int y, int od=0, int cp=70) :Car(maker, model, y, od), battery(cp) {}
    void info()const;
};

void ElectricCar::info()const {
    Car::info();
    cout << left << setw(15) << "capacity:" << battery.get_capacity() << "-kwh" << endl;
}
#endif // !_ELECTRICCAR_HPP

#include <iostream>
#include "ElectricCar.hpp"

int main()
{
    using namespace std;

    // test class of Car
    Car oldcar("Audi", "q7", 2017);
    cout << "--------oldcar's info--------" << endl;
    oldcar.update_odometers(13000);
    oldcar.info();

    cout << endl;

    // test class of ElectricCar
    ElectricCar newcar("Tesla", "model s", 2015);
    newcar.update_odometers(1145);
    cout << "\n--------newcar's info--------\n";
    newcar.info();
    return 0;
}

 

 

#ifndef _PETS_HPP
#define _PETS_HPP
#include<string>
#include<windows.h>
#include<Mmsystem.h>
#pragma comment(lib,"winmm.lib")
using namespace std;
class MachinePets {
private:
    string nickName;
public:
    MachinePets(const string name):nickName(name){}
    virtual string talk() const { return static_cast<string>("a interface "); }
     string get_nickName()const;
};

string MachinePets::get_nickName()const {
    return nickName;
}
class PetCats:public MachinePets {
public:
    PetCats(const string name):MachinePets(name){}
    string talk()const;
};
string PetCats::talk()const {
    string s = get_nickName() + " says miao wu~";
    PlaySound(TEXT("./cat.wav"), NULL, SND_FILENAME| SND_NODEFAULT);
    return s;
}



class PetDogs :public MachinePets {
public:
    PetDogs(const string name) :MachinePets(name) {}
    string talk()const;
};
string PetDogs::talk()const {
    string s = get_nickName() + " says wang wang~";
    PlaySound(TEXT("./dog.wav"), NULL, SND_FILENAME);
    return s;
}
#endif // !_PETS_HPP

 

#include<iostream>
#include "pets.hpp"

void play(MachinePets* ptr)
{
    std::cout  << ptr->talk() << std::endl;
}

int main()
{
    PetCats cat("miku");
    
    PetDogs dog("da huang");

    play(&cat);
    //pause
    system("pause");
    play(&dog);
    return 0;
}

 

 

#include<iostream>
#include<map>
#include <string>
#include<stack>
using namespace std;

void fun01() {
    map<char, char > dict{ {'0','a'},{'1','b'} ,{'2','c'} ,{'3','d'} ,{'4','e'} ,{'5','f'} ,{'6','g'} ,{'7','h'} ,{'8','i'} ,{'9','j'}};
    string num;
    cin >> num;
    for (auto& i : num) 
        cout << dict[i];
    cout << endl;
    
}

void fun02(int x,int n = 2) {
    if (n == 8)cout <<showbase<< uppercase << oct << x << endl;
    else if (n == 16)cout << showbase << uppercase << hex << x << endl;
    else {
        stack<int> s;
        while (x) {
            s.push(x % 2);
            x /= 2;
        }
        while (!s.empty()) {
            cout << s.top();
            s.pop();
        }
        cout << endl;
    }
}