Question

Exercise 2: There can be several constructors as long as they differ in number of parameters or data type. Alter the program so that the user can enter just the radius, the radius and the center, or nothing at the time the object is defined. Whatever the user does NOT include (radius or center) must be initialized somewhere. There is no setRadius function and there will no longer be a setCenter function. You can continue to assume that the default radius is 1 and the default center is (0, 0). Alter the client portion (main) of the program by defining an object sphere1, giving just the radius of 2 and the default center, and sphere2 by giving neither the radius nor the center (it uses all the default values). Be sure to print out the vital statistics for these new objects (area and circumference).

Code:

#include<iostream>

using namespace std;

class Circles

{

private:

       float radius;

       int    center_x;

       int    center_y;

public:

       void setCenter(int x, int y);

       double findArea();

       double findCircumference();

       void printCircleStats(); // This outputs the radius and center of the circle.

       Circles(float r);       // Constructor

       Circles();               // Default constructor

};

const double PI = 3.14;

//you can remove this constrctor

//Client section

//Circles::Circles()

//{

//   radius = 1;

//}

Circles::Circles()

{

       center_x = 9;

       center_y = 10;

       //initialize the radius with 8

       radius = 8;

}

double Circles::findArea()

{

       return 3.14*radius*radius;

}

double Circles::findCircumference()

{

       return 2 * 3.14*radius;

}

void Circles::printCircleStats()

{

       cout << "The radius of the circle is " << radius << endl;

       cout << "The center of the circle is (" << center_x << "," << center_y << ")" << endl;

}

void Circles::setCenter(int x, int y)

{

       center_x = x;

       center_y = y;

}

int main()

{

       //Circles sphere(8);

       //create an object to Circles and default constructor will call with pre assigned

       //initial values

       Circles sphere;

       // sphere.setCenter(9,10);

       sphere.printCircleStats();

       cout << "The area of the circle is " << sphere.findArea() << endl;

       cout << "The circumference of the circle is " << sphere.findCircumference() << endl;

       system("pause");

       return 0;

}

Answer 1

#include <iostream>

using namespace std;

class Circles

{

private:

       float radius;

       int    center_x;

       int    center_y;

public:

       //void setCenter(int x, int y);

       double findArea();

       double findCircumference();

       void printCircleStats(); // This outputs the radius and center of the circle.

       Circles(float r);       // parameterized Constructor

       Circles(float r, int centerX, int centerY); // parameterized constructor

       Circles();               // Default constructor

};

const double PI = 3.14;

//you can remove this constrctor

//Client section

//Circles::Circles()

//{

//   radius = 1;

//}

Circles::Circles()

{

               // initialize the Circle with default values

       center_x = 0;

       center_y = 0;

       radius = 1;

}

Circles::Circles(float r)       // parameterized Constructor with radius given

{

               radius = r;

               center_x = 0;

               center_y = 0;

}

Circles::Circles(float r, int centerX, int centerY) // parameterized constructor with radius and center given

{

               radius = r;

               center_x = centerX;

               center_y = centerY;

}

double Circles::findArea()

{

       return 3.14*radius*radius;

}

double Circles::findCircumference()

{

       return 2 * 3.14*radius;

}

void Circles::printCircleStats()

{

       cout << "The radius of the circle is " << radius << endl;

       cout << "The center of the circle is (" << center_x << "," << center_y << ")" << endl;

}

/*void Circles::setCenter(int x, int y)

{

       center_x = x;

       center_y = y;

}*/

int main() {

               //Circles sphere(8);

                      //create an object to Circles and default constructor will call with pre assigned

                      //initial values

               /*      Circles sphere;

                      // sphere.setCenter(9,10);

                      sphere.printCircleStats();

                      cout << "The area of the circle is " << sphere.findArea() << endl;

                      cout << "The circumference of the circle is " << sphere.findCircumference() << endl;

*/

               Circles sphere1(2),sphere2;

               cout<<" Sphere 1 : "<<endl;

               sphere1.printCircleStats();

               cout << "The area of the circle is " << sphere1.findArea() << endl;

   cout << "The circumference of the circle is " << sphere1.findCircumference() << endl;

    cout<<" Sphere 2 : "<<endl;

    sphere2.printCircleStats();

    cout << "The area of the circle is " << sphere2.findArea() << endl;

    cout << "The circumference of the circle is " << sphere2.findCircumference() << endl;

system("pause");

               return 0;

}

//end of program

Output: