定义一个基类Shape,在此基础上派生出Rectangle和Circle,二者都有getArea()函数计算对象的面积。使用Rectangle类创建一个派生类Square。
1 #include <iostream>
2 #include <string>
3 #include<string.h>
4 #include <stdio.h>
5 using namespace std;
6
7 class Shape{
8 public:
9 virtual double getArea(){return -1;}
10 };
11
12 class Rectangle:public Shape{
13 private:
14 double length;
15 double width;
16 public:
17 Rectangle(){length = 1; width = 1;}
18 Rectangle(double length, double width):length(length), width(width){}
19 double getArea(){return length * width;}
20 ~Rectangle(){}
21 };
22
23 class Circle:public Shape{
24 private:
25 double r;
26 public:
27 Circle(){r = 1;}
28 Circle(double r):r(r){}
29 double getArea(){return 3.14 * r * r;}
30 ~Circle(){}
31
32 };
33
34 class Square:public Rectangle{
35 private:
36 double length;
37 public:
38 Square(){length = 1;}
39 Square(double len):length(len){}
40 double getArea(){return length * length;}
41 ~Square(){}
42 };
43
44
45 int main(){
46 Shape *test = new Rectangle(1,10);
47 cout<<"矩形面积："<<test->getArea()<<endl;
48 delete test;
49 test = new Circle(10);
50 cout<<"圆形面积："<<test->getArea()<<endl;
51 delete test;
52 test= new Square(5);
53 cout<<"正方形面积："<<test->getArea()<<endl;
54 delete test;
55 return 0;
56
57 }
标签：,getArea,double,width,length,public,Rectangle From： https://www.cnblogs.com/YUZE2001/p/17224551.html