13th Week "Project 2-pure virtual function in the shape class family"

Description of the problem:

Write a program. Defines the abstract base class shape, which derives 3 derived classes, Circle (circle), Rectangle (Rectangle), Triangle (triangle). Use the main () function such as the following. Find the area and the number of geometry defined.

int main () {    Circle C1 (12.6), C2 (4.9);//Create Circle Class object c1,c2 with radius    Rectangle R1 (4.5,8.4), R2 (5.0,2.5);// Establish the Rectangle class object R1,R2, the length of the rectangle, the width    Triangle T1 (4.5,8.4), T2 (3.4,2.8);//Build Triangle Class object T1,t2, the number of the triangle is the length of the bottom and the high    Shape *pt [6]= {&c1,&c2,&r1,&r2,&t1,&t2}; Defines the base class pointer array pt. Make it each element point to a derived class object    double areas=0.0;//areas for 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;}

Code:

#include <iostream> #include <cmath> #define PI 3.14159using namespace Std;class shape{public:virtual double Area () = 0;}; Class Circle:public shape{private:double r;public:circle (double a=0): R (a) {} double area () {return r*r*pi;}}; Class Rectangle:public shape{private:double L,w;public:rectangle (double A, double b): L (a), W (b) {} double area () { return l*w;}; Class Triangle:public shape{private:double H,l;public:triangle (double a,double b): H (a), L (b) {} double area () {RET Urn H*L/2;}}; int main () {Circle C1 (12.6), C2 (4.9),//Create Circle Class object C1,c2, Radius Rectangle R1 (4.5,8.4), R2 (5.0,2.5),//Build Rectangle class object R1, R2, the parameters are rectangular length, width Triangle T1 (4.5,8.4), T2 (3.4,2.8); Establish the Triangle Class object T1,t2, which is the triangle bottom length and the 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;} 

Execution Result:

13th Week "Project 2-pure virtual function in the shape class family"