Question

In C++,

Write a Circle class that has the following member variables:

• radius : a double

The class should have the following member functions:

• Default Constructor: default constructor that sets radius to 0.0.

• Constructor: accepts the radius of the circle as an argument.

• setRadius: an mutator function for the radius variable.

• getRadius: an accessor function for the radius variable.

• getArea: returns the area of the circle, which is calculated as area = pi * radius * radius

• getCircumference: returns the circumference of the circle, which is calculated as circumference = 2 * pi * radius

Step1: Create a declaration of the class.

Step2: Write a program that demonstrates the Circle class by asking the user for the circle’s radius, creating

a Circle object, and then reporting the circle’s area, and circumference.

Answer 1

#include <iostream>

using namespace std;

#define pi 3.14159

class Circle
{
private:
   double radius;
public:
   Circle();
   Circle(double r);
   void setRadius(double);
   double getRadius();
   double getArea();
   double getCircumference();
};

Circle::Circle() {
   radius = 0;
}

Circle::Circle(double r) {
   setRadius(r);
}

void Circle::setRadius(double r) {
   radius = r;
}

double Circle::getRadius() {
   return radius;
}

double Circle::getArea() {
   return pi * radius * radius;
}

double Circle::getCircumference() {
   return 2 * pi * radius;
}

int main() {
   Circle circle;
   double radius;
   cout << "Enter radius of circle: ";
   cin >> radius;
   circle.setRadius(radius);
   cout << "Area: " << circle.getArea() << endl;
   cout << "Circumference: " << circle.getCircumference() << endl;
   return 0;
}