13th Week Item 2-pure virtual functions in the Shape class family

Write a program that defines the abstract base class shape, derived from it by 3 derived classes, Circle (circle), Rectangle (Rectangle), Triangle (triangle). Use the following main () function to find the area and the number of geometry defined.

int main () {    Circle C1 (12.6), C2 (4.9),//Create Circle Class object C1,c2, parameters are circle radius    Rectangle R1 (4.5,8.4), R2 (5.0,2.5);// Establish the Rectangle class object R1,R2, the parameters are rectangle length, width    Triangle T1 (4.5,8.4), T2 (3.4,2.8),//Triangle class object T1,t2, the parameters are triangular bottom length and high    Shape *pt [6]= {&c1,&c2,&r1,&r2,&t1,&t2}; Defines the base class pointer array pt, which points each element to a derived class object    double areas=0.0;//areas for the total area for    (int i=0; i<6; i++)    {        Areas=areas + Pt[i]->area ();    }    cout<< "Totol of all areas=" <<areas<<endl;   Output total area    return 0;}

/** Copyright (c) 2015, Yantai University School of Computer * All right reserved.* Shao * file: demo.cpp* finish: June 07, 2015 * version number: v1.0*/#include <iostream > #include <string>using namespace std;class shape{public:virtual Double area () = 0;};        Class Circle:public shape{private:double radius;public:circle (Double R): Radius (r) {} virtual double area () {    return (3.14*radius*radius);    }};class rectangle:public shape{private:double Leight; Double Height;public:rectangle (double l,double h): Leight (L), height (h) {} virtual double area () {return (l    Eight*height);    }};class triangle:public shape{private:double underline; Double Height;public:triangle (double u,double h): Underline (U), height (h) {} virtual double area () {return    (UNDERLINE*HEIGHT*1/2); }};int Main () {Circle C1 (12.6), C2 (4.9),//Create Circle Class object C1,c2, parameter is circle radius Rectangle R1 (4.5,8.4), R2 (5.0,2.5);//Build Rectangle Class object R1,R2, the parameters are rectangle length, width Triangle T1 (4.5,8.4), T2 (3.4,2.8);  Establishes the Triangle class object T1,t2, the parameter is the triangle bottom length and the height  Shape *pt[6]= {&c1,&c2,&r1,&r2,&t1,&t2}; Defines the base class pointer array pt, which points each element to a derived class object double areas=0.0;    Areas for the total area for (int i=0; i<6; i++) {areas=areas + Pt[i]->area ();   } cout<< "Totol of all areas=" <<areas<<endl; Output total area return 0;}

Operation Result:

@ Mayuko

13th Week Item 2-pure virtual functions in the Shape class family