实验4 继承
作者：互联网
实验二
1 #include <iostream>
2 #include <typeinfo>
3
4 // definitation of Graph
5 class Graph
6 {
7 public:
8 void draw() { std::cout << "Graph::draw() : just as an interface\n"; }
9 };
10
11
12 // definition of Rectangle, derived from Graph
13 class Rectangle : public Graph
14 {
15 public:
16 void draw() { std::cout << "Rectangle::draw(): programs of draw a rectangle\n"; }
17 };
18
19
20 // definition of Circle, derived from Graph
21 class Circle : public Graph
22 {
23 public:
24 void draw() { std::cout << "Circle::draw(): programs of draw a circle\n"; }
25 };
26
27
28 // definitaion of fun(): as a call interface
29 void fun(Graph *ptr)
30 {
31 std::cout << "pointer type: " << typeid(ptr).name() << "\n";
32 std::cout << "RTTI type: " << typeid(*ptr).name() << "\n";
33 ptr -> draw();
34 }
35
36 // test
37 int main()
38 {
39 Graph g1;
40 Rectangle r1;
41 Circle c1;
42
43 // call by object name
44 g1.draw();
45 r1.draw();
46 c1.draw();
47
48 std::cout << "\n";
49
50 // call by object name, and using the scope resolution operator::
51 r1.Graph::draw();
52 c1.Graph::draw();
53
54 std::cout << "\n";
55
56 // call by pointer to Base class
57 fun(&g1);
58 fun(&r1);
59 fun(&c1);
60 }
没有添加virtual
添加virtual
* 对于同名的函数，继承类将覆盖基类的函数 * 对于继承的类，可以通过继承类::函数的方式去访问被隐藏的函数 * 在需要基类对象的任何地方,都可以使用公有派生类的对象来替代。 * 在增添了virtual后，fun()函数输出发生了变化。通过重写虚拟函数来实现对基类虚拟函数的覆盖。
实验任务3
battery.hpp
1 #include<iostream>
2 using namespace std;
3
4 class Battery{
5 public:
6 Battery(int ca = 70) : capacity(ca) {} ;
7 int get_capacity(){
8
9 return capacity;
10 }
11 private:
12 int capacity;
13 };
car.hpp
1 #include<iostream>
2 #include<string>
3 using namespace std;
4
5 class Car{
6 public:
7 Car(string ma, string mo, int y, int od = 0) : maker(ma), model(mo), year(y), odometers(od) {} ;
8 void info(){
9 cout<<"maker\t\t"<<maker<<endl;
10 cout<<"model\t\t"<<model<<endl;
11 cout<<"year:\t\t"<<year<<endl;
12 cout<<"odometerd:\t"<<odometers<<endl;
13 }
14 void update_odometers(int od){
15 if(od < odometers)
16 cout<<"The update_odometers is wrong"<<endl;
17 else
18 odometers = od;
19 }
20 private:
21 string maker;
22 string model;
23 int year;
24 int odometers;
25 };
electricCar.hpp
1 #include<iostream>
2 #include"battery.hpp"
3 #include"car.hpp"
4
5 using namespace std;
6
7 class ElectricCar : public Car{
8 public:
9 ElectricCar(string ma, string mo, int y, int od = 0, int ba = 70) : Car(ma, mo, y, od), battery(ba) {} ;
10 void info(){
11 Car::info();
12 cout<<"capacity:\t"<<battery.get_capacity()<<"-KWh"<<endl;
13 }
14 private:
15 Battery battery;
16 };
task3.cpp
1 #include <iostream>
2 #include "electricCar.hpp"
3
4 int main()
5 {
6 using namespace std;
7
8 // test class of Car
9 Car oldcar("Audi", "a4", 2019);
10 cout << "--------oldcar's info--------" << endl;
11 oldcar.update_odometers(2500);
12 oldcar.info();
13
14 cout << endl;
15
16 // test class of ElectricCar
17 ElectricCar newcar("Tesla", "model s", 2021);
18 newcar.update_odometers(2900);
19 cout << "\n--------newcar's info--------\n";
20 newcar.info();
21 }
实验任务四
pets.hpp
1 #include<iostream>
2 #include<string>
3 using namespace std;
4
5 class MachinePets{
6 public:
7 MachinePets(const string s) : nickname(s) {} ;
8 string get_nickname() const{
9 return nickname;
10 }
11 virtual string talk() {};
12 private:
13 string nickname;
14 };
15
16 class PetCats : public MachinePets{
17 public:
18 PetCats(const string s) : MachinePets(s) {} ;
19 string talk(){
20 return "miao wu~";
21 }
22 };
23
24 class PetDogs : public MachinePets{
25 public:
26 PetDogs(const string s) : MachinePets(s) {} ;
27 string talk(){
28 return "wang wang~";
29 }
30 };
task4.cpp
1 #include <iostream>
2 #include "pets.hpp"
3
4 void play(MachinePets *ptr)
5 {
6 std::cout << ptr->get_nickname() << " says " << ptr->talk() << std::endl;
7 }
8
9 int main()
10 {
11 PetCats cat("miku");
12 PetDogs dog("da huang");
13
14 play(&cat);
15 play(&dog);
16 }
标签：std,string,继承,hpp,int,实验,include,public 来源： https://www.cnblogs.com/YJJZ/p/15589319.html