calculate dimensions of a circle in c++

Code:

---

#ifndef CIRCLE_H
#define CIRCLE_H

class Circle {
public:
  //constructors
  Circle();
  Circle(double r);
  //setter
  void setRadius(double r);
  //getter
  double getRadius();
  //calculate the diameter of a circle
  double computeDiameter()const;
  //calculate the area of a circle
  double computeArea()const;
  //calculate the Circumference of a circle
  double computeCircumference()const;
  //checks if radius of circle is bigger
  **bool isBigger(const Circle& other) const;**

private:
  //private data members
  double m_Radius;
};

#endif // CIRCLE_H



#include "circle.h"
#include "math.h"
#include <iostream>
#include <QString>
#include <sstream>
using namespace std;

Circle::Circle()
{
  m_Radius =  0;
}

Circle::Circle(double r)
{
  m_Radius = r;
}

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

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

double Circle::computeDiameter()const{
    return 2* m_Radius;
}

double Circle::computeArea()const {
    return ( m_Radius* m_Radius*M_PI);
}

double Circle::computeCircumference()const {
    return (2* m_Radius*M_PI);
}


#include <iostream>
#include <QTextStream>
#include "circle.h"
using namespace std;

int main(){
    QTextStream cout(stdout);

    Circle c1,c2;    // input
    c1.setRadius(3);
    c2.setRadius(7);

    cout << "Circle with radius " << c1.getRadius() << " has: " << endl;
    cout<< "Diameter " << c1.computeDiameter() << " cm " <<endl;
    cout<< "Area " << c1.computeArea() << " cm" <<endl;
    cout<< "Circumference " << c1.computeCircumference()<< " cm " <<endl<<endl;

    cout << "Circle with radius " << c2.getRadius() << " has: " << endl;
    cout<< "Diameter " << c2.computeDiameter() << " cm " <<endl;
    cout<< "Area " << c2.computeArea() << " cm" <<endl;
    cout<< "Circumference " << c2.computeCircumference()<< " cm " <<endl<<endl;

return 0;
}

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The function isBigger() returns true (or false) if the radius of the Circle instance on which the function is invoked is bigger (or smaller) than the radius of the Circle instance passed to the function.: Can someone help me to implement this function?

First of all, please use code tags when posting source code.

Then, never place a "using" directive in a header file. For a discussion, see this link: http://stackoverflow.com/questions/5...e-in-c-headers

What is your problem with the isBigger function? It is quite forward to implement.

I added this code in main

[code]if(c1.isBigger(c2))
cout << "circle 1 is bigger" << endl;
else
cout << "circle 2 is bigger" << endl;[\code]


and it works. What do u think? The function is:

[code]bool Circle::isBigger(const Circle& other) const {
return m_Radius > other.m_Radius;
}[\code]

I added this code in main

Code:

---

if(c1.isBigger(c2))
              cout << "circle 1 is bigger"  << endl;
            else
              cout << "circle 2 is bigger"  << endl;

---

and it works. What do u think? The function is:

Code:

---

bool Circle::isBigger(const Circle& other) const {
            return m_Radius > other.m_Radius;
        }

---

Yes, that's what I was thinking of, but didn't want to post because it is so simple.

1) There is no need to have two constructors in this case. Just have one with a default argument of 0.

2) getRadius should be const as it only returns a value

3) isBigger would usually be implemented via overloading the > operator. Also the <, == and != operators would also be overloaded allowing statements like c1 > c2 and c2 != c1. A possible way of doing this is

Code:

---

#include <iostream>
using namespace std;

const double M_PI = 3.1416;

class Circle {
public:

        //constructors
        Circle(double r = 0);

        //setter
        void setRadius(double r);

        //getter
        double getRadius() const;

        //calculate the diameter of a circle
        double computeDiameter() const;

        //calculate the area of a circle
        double computeArea() const;

        //calculate the Circumference of a circle
        double computeCircumference() const;

        //checks if radius of circle is bigger
        bool isBigger(const Circle& other) const;

        //operator overloads
        bool operator> (const Circle& other) const;
        bool operator< (const Circle& other) const;
        bool operator== (const Circle& other) const;
        bool operator!= (const Circle& other) const;

private:
        //private data members
        double m_Radius;
};

Circle::Circle(double r)
{
        m_Radius =  r;
}

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

double Circle::getRadius() const
{
    return m_Radius;
}

double Circle::computeDiameter() const
{
        return 2 * m_Radius;
}

double Circle::computeArea() const
{
        return m_Radius * m_Radius * M_PI;
}

double Circle::computeCircumference() const
{
        return 2 * m_Radius * M_PI;
}

bool Circle::isBigger(const Circle& other) const
{
            return m_Radius > other.m_Radius;
}


bool Circle::operator >(const Circle& other) const
{
        return m_Radius > other.m_Radius;
}

bool Circle::operator <(const Circle& other) const
{
        return m_Radius < other.m_Radius;
}

bool Circle::operator ==(const Circle& other) const
{
        return m_Radius == other.m_Radius;
}

bool Circle::operator !=(const Circle& other) const
{
        return m_Radius != other.m_Radius;
}

int main(){
Circle c1,c2;    // input

        c1.setRadius(3);
        c2.setRadius(7);

        cout << "Circle with radius " << c1.getRadius() << " has: " << endl;
        cout<< "Diameter " << c1.computeDiameter() << " cm " << endl;
        cout<< "Area " << c1.computeArea() << " cm" << endl;
        cout<< "Circumference " << c1.computeCircumference()<< " cm " << endl << endl;

        cout << "Circle with radius " << c2.getRadius() << " has: " << endl;
        cout << "Diameter " << c2.computeDiameter() << " cm " <<endl;
        cout << "Area " << c2.computeArea() << " cm" <<endl;
        cout << "Circumference " << c2.computeCircumference() << " cm " << endl << endl;

        if (c1.isBigger(c2))
                cout << "circle 1 is bigger"  << endl;
        else
                cout << "circle 2 is bigger"  << endl;

        if (c1 < c2)
                cout << "circle 2 is bigger"  << endl;
        else
                cout << "circle 1 is bigger"  << endl;

        if (c1 != c2)
                cout << "circle 1 is not equal to c2"  << endl;
        else
                cout << "circle 1 is equal to c2"  << endl;

        return 0;
}

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