Question

Hi, please provide a code solution written in the C++ language to the following programming problem. The answer you provide has to include code comments, as it is being explained to a person with no technical background. In your answer, please show which portion of the code is a .cpp and which is a .h (if used). We are asked to separate them out (ie. main.cpp, classname.cpp, headername.h). Please show the output of your program to show it compiled error free. Thanks!

SEE PROGRAMMING PROBLEM BELOW

Answer 1

main.cpp

// This program demonstrates an abstract base class and overriding a pure virtual function
// This program creates a Circle object and a Rectangle object (both derived from the
// BasicShape class) and displays their areas

#include <iostream>
#include "Circle.h"
#include "Rectangle.h"
using namespace std;

void displayArea(BasicShape* shape);

int main()
{
       // create a Circle object pointer - cirPtr
       // create a Circle object - cir
       // point the pointer to the object's address
   Circle *cirPtr = nullptr;
   Circle cir(5, 2, 3.0);
   cirPtr = &cir;

       // create a Rectangle object pointer - recPtr
       // create a Rectangle object - rec
       // point the pointer to the object's address
   Rectangle *recPtr = nullptr;
   Rectangle rec(7, 8);
   recPtr = &rec;

       // call the displayArea function on both shapes to display the area
   displayArea(cirPtr);
   displayArea(recPtr);

   system("pause");
   return 0;
}

// this function displays the area of the shape passed to it
void displayArea(BasicShape* shape)
{
   cout << shape->getArea() << endl;
}

Rectangle.h

// This Rectangle class is derived from the BasicShape class. it has a width and lengh attribute
// used to calculate the area (a virtual function overridden from the BasicShape class)

#ifndef RECTANGLE_H
#define RECTANGLE_H

#include "BasicShape.h"

class Rectangle : public BasicShape
{
private:
   long width;
   long length;
public:
   // constructor
   Rectangle(long, long);

   // getters
   long getWidth() const;
   long getLength() const;

   // overriden function from BasicShape class
   virtual double calcArea();
};
#endif

BasicShape.cpp

// This BasicShape class is a generic shape with an area, a function to return the area, and a virtual function
// to be overridden by derived classes to calculate the area

#include "BasicShape.h"

// getter
double BasicShape::getArea() const
{
   return area;
}

Circle.cpp

// This Circle class is derived from the BasicShape class. it has a centerX and CenterY coordinates, as well
// as a radius attributes used to calculate the area (a virtual function overridden from the BasicShape class)

#include "Circle.h"

// constructor
Circle::Circle(long x, long y, double r)
{
   centerX = x;
   centerY = y;
   radius = r;

   calcArea();
}

// getters
long Circle::getCenterX() const
{
   return centerX;
}

long Circle::getCenterY() const
{
   return centerY;
}

// overriden virtual function from the BasicShape class
double Circle::calcArea()
{
   area = 3.14159 * radius * radius;
   return area;
}

Circle.h

#ifndef CIRCLE_H
#define CIRCLE_H

#include "BasicShape.h"

class Circle : public BasicShape
{
private:
   long centerX;
   long centerY;
   double radius;
public:
   // constructor
   Circle(long, long, double);

   // getters
   long getCenterX() const;
   long getCenterY() const;

   // overriden function from BasicShape class
   virtual double calcArea();
};
#endif

BasicShape.h

#ifndef BASICSHAPE_H
#define BASICSHAPE_H

class BasicShape
{
protected:
        double area;
public:
        // getter
        double getArea() const;

        // virtual function to be overriden by derived classes
        virtual double calcArea() = 0;
};
#endif

Rectangle.cpp

#include "Rectangle.h"

// constructor
Rectangle::Rectangle(long w, long l)
{
        width = w;
        length = l;
        calcArea();
}

// getters
long Rectangle::getWidth() const
{
        return width;
}

long Rectangle::getLength() const
{
        return length;
}

// overriden virtual function from the BasicShape class
double Rectangle::calcArea()
{
        area = width * length;
        return area;
}