Programming Challenge 15.13 - Pure Abstract Base Class Project

Example Files: PureAbstractBaseClass.7z
                          PureAbstractBaseClassAlt.7z

Notice: This challenge has been solved in two ways. The first one is written according to the problem statement on page 986. The other solution is based on code kindly provided to this person, who only adapted the code a little.

BasicShape.h

#ifndef BASIC_SHAPE_H_
#define BASIC_SHAPE_H_

class BasicShape
{
    protected:
        double area;

    public:
        virtual ~BasicShape()
        {
        }

        double getArea() const
        { return area; }

        virtual void calcArea() = 0;
};

#endif

Circle.h

#ifndef CIRCLE_H_
#define CIRCLE_H_

#include "BasicShape.h"

class Circle : public BasicShape
{
    private:
        long   centerX;
        long   centerY;
        double radius;

    public:
        Circle(long, long, double);

        ~Circle()
        {
        }

        // Accessors
        long getCenterX() const
        { return centerX; }

        long getCenterY() const
        { return centerY; }

        double getRadius() const
        { return radius; }

        virtual void calcArea() override;
};

#endif

Circle.cpp

#include "Circle.h"

/* **********************************************************
            Rectangle::Rectangle() - long, long, double
         - Constructor
   ********************************************************** */

Circle::Circle(long xCoord, long yCoord, double rad) : BasicShape()
{
    centerX = xCoord;
    centerY = yCoord;
    radius = rad;

    this->calcArea();
}

/* **********************************************************
            Circle::calcArea()
    Calculates the area of a circle object, and assigns the
    result to the inherited area member variable.
   ********************************************************** */

void Circle::calcArea()
{
    area = (3.14159 * (radius * radius));
}

Rectangle.h

#ifndef RECTANGLE_H_
#define RECTANGLE_H_

#include "BasicShape.h"

class Rectangle : public BasicShape
{
    private:
        long length;
        long width;

    public:
        Rectangle(long, long);
       
        ~Rectangle()
        {
        }

        long getLength() const
        { return length; }

        long getWidth() const
        { return width; }

        virtual void calcArea() override;
};

#endif

Rectangle.cpp

#include "Rectangle.h"

/* **********************************************************
            Rectangle::Rectangle() : long, long
         - Constructor
   ********************************************************** */

Rectangle::Rectangle(long rectLength, long rectWidth) : BasicShape()
{
    width = rectLength;
    length = rectWidth;

    this->calcArea();
}

/* **********************************************************
            Rectangle::calcArea()
    Calculates and returns the area of a rectangle object and
    assigns the result to the inherited area member variable.
   ********************************************************** */

void Rectangle::calcArea()
{
    area = (length * width);
}

BasicShapeDm.cpp

#include "Circle.h"
#include "Rectangle.h"

#include <array>
using std::array;

#include <iomanip>
using std::setprecision;

#include <iostream>
using std::cin;
using std::cout;
using std::fixed;

#include <string>
using std::string;

int main()
{
    const int NUM_OBJ = 2;

    // Dynamically created shape objects
    Circle *circle = new Circle(4, 4, 5.74);
    Rectangle *rectangle = new Rectangle(15, 7);

    // Array of pointers to shape objects
    array<BasicShape *, NUM_OBJ> shapes { circle, rectangle };

    // Array of shape names
    array<string, NUM_OBJ> shapeName { "Circle   ", "Rectangle" };

    cout << "'PURE' ABSTRACT BASE CLASS DEMO\n\n";

    cout << "Circle Data\n\n";
    cout << "Center X: " << circle->getCenterX() << "\n";
    cout << "Center Y: " << circle->getCenterY() << "\n";
    cout << "Radius:   " << circle->getRadius()  << "\n\n";

    cout << "Recatangle Data\n\n";
    cout << "Length:   " << rectangle->getLength() << "\n";
    cout << "Width:    " << rectangle->getWidth() << "\n\n";

    cout << "The area of your shapes is:\n\n";
    cout << fixed << setprecision(2);
   
    for (size_t i = 0; i < shapes.size(); i++)
    {
        cout << shapeName[i] << ": " << shapes[i]->getArea() << " mm\n";
    }

    cout << "\nThank you for using this 'pure' demo! Have a nice day!";

    delete circle;
    delete rectangle;
   
    cin.get();
    cin.ignore();
    return 0;
}

Example Output: