Question

C++ please

#include <iostream>

using namespace std;

/**
* defining class circle
*/
class Circle
{
    //defining public variables
public:
    double pi;
    double radius;
public:

   //default constructor to initialise variables
   Circle(){
      pi = 3.14159;
      radius = 0;
   }
   
   Circle(double r){
          pi = 3.14159;
          radius = r;
   }

   // defining getter and setters
   void setRadius(double r){
       radius = r;
   }
   double getRadius(){
      return radius;
   }

   // method to get Area
   double getArea(){
      return pi*radius*radius;
   }
};

//main method
int main()
{
    //declaring and taking input of radius
    double r;
    cout<<"Enter radius: ";
    cin>>r;
  
    //making an object of class circle
    Circle c(r);
  
    //printing area of circle
    cout<<"Area = "<<c.getArea()<<endl;
}

Write a for loop that displays the radius and area of the circles represented by the array you defined in the source code above.

Answer 1

//----------- Circle.cpp -----------
#include <iostream>
#include<limits>
using namespace std;

/**
* defining class circle
*/
class Circle
{
//defining public variables
public:
double pi;
double radius;
public:

//default constructor to initialise variables
Circle(){
pi = 3.14159;
radius = 0;
}

Circle(double r){
pi = 3.14159;
radius = r;
}

// defining getter and setters
void setRadius(double r){
radius = r;
}
double getRadius(){
return radius;
}

// method to get Area
double getArea(){
return pi*radius*radius;
}
};

//function that checks if cin is failed or not
//fail means invalid type is inputted for a variable.
//like giving string instead of number .
bool isInvalidInput()
{
   //if cin is fail
   if(cin.fail())
   {
       //clear the buffer.
       cin.clear();
       //ignore the characters.it need limits header.
       cin.ignore(numeric_limits<streamsize>::max(),'\n');
       return true;
   }
   //if not return false.
   return false;
}

//main method
int main()
{
   //get number of circles to be created from user as input.
   int n;
   cout<<"Enter Number of circles want to create: ";
   cin >> n;
   //if invalid input like entering string for n or n is <= 0;
   //print error msg and exit
   if(isInvalidInput() || n <= 0 )
   {
       cout<<"Invalid number of circles entered\n";
       exit(1);
   }
   //array of circle.
   Circle circles[n];
//radius
double r;
//get n number of circles from user.
for(int i =0;i<n;i++)
{
       cout<<"\nEnter radius: ";
       //get raidus
       cin>>r;
       //check for invalid input, if invalid set radisu to 1
       if(isInvalidInput())
       {
           cout<<"Invalid radius entered,setting radius to 1."<<endl;
           r = 1;
       }
       //create a neew circle object for the given radius.
       Circle circle(r);
       //insert in circles array
       circles[i] = circle;
   }
  
   //print the radius and the area of the circle in circles array.
   for(int i =0;i<n;i++)
   {
       cout<<"\nRadius: "<<circles[i].getRadius()<<" , Area: "<<circles[i].getArea()<<endl;
   }
   return 0;
}
//------------- SAMPLE OUTPUT -----------

//please like the answer.