#include <iostream>                  // This includes some file we need.
#include <string>                  // This includes some file we need.
using namespace std;               // This says we're using namespace std [ I think :X ].
int main() {                     // This starts the main program.

   system("Color 17");               // Turns the background blue[1] and the font white[7].
   double radius;                  // This instalizes the radius input.
   string response;               // This instalizes the response string.
   cout << "What is the radius? ";     // Prints "What is the radius?".
   cin >> radius;                  // This inputs the radius.

   cout <<  "\nCircumference = " << (radius)*(3.14)*(2) << endl;   // This sends out the circumference.
   cout << "Area = " << (radius)*(radius)*(3.14) << endl;            // This sends out the area.
   cout << "\nWould you like to do another one? [Y/N]" << endl; // Asks you if you want to do it again.
   cin >> response;    // Input for Yes or No.
   
   if(response == "Y")    // If user types "Y" they are sent to repeat what just happened.
   {
      cout << "\n" << endl;
      main();  // Returns to what went on previously.
   }

   if(response == "y")   // If user types "y" [lower-case 'y'] they are sent to repeat what just happened.
   {
      cout << "\n" << endl;
      main();  // Returns to what went on previously.
   }

   if(response == "N")    // If user types "N" the program exits.
   {
      exit(0);  // Exits the program.
   }

    if(response == "n")    // If user types "n" [lower-case 'n'] the program exits.
   {
      exit(0);  // Exits the program.
   }

   else   // If neither Y(y) or N(n) is entered after radius.
   {
        system("cls");  // Clears the whole prompt screen.
        main();         // Returns to starting point.
   }

}

/*
This is open source to all.
This is a simple way to get the circumerence of a circle and the area.
It is pretty basic and pointless.
*/

import java.io.*;
import java.util.*;
 
   public class Circles{
   public Circles(){}

   public static void main(String [] args){

    try {
System.out.println( "What is the radius?  " );
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        String str = "";
        while (str != null) {
            str = in.readLine();
System.out.println( "\n Circumference = " + ( Double.valueOf(str) )*(2)*(3.14) );
System.out.println( " Area = " + ( Double.valueOf(str) )*( Double.valueOf(str) )*(3.14) );
System.out.println( "\nWhat is the radius?" );
}
    } catch (Exception e) {
    }

}
}

#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main() {

   system("Color 17");
   double radius;
   string response;
   int i;

   for( i = 0; i < 10; i++ )
   {
      goto mainf;
   }

   mainf:
      cout << "What is the radius? ";
      cin >> radius;
      cout <<  "\nCircumference = " << (radius)*(3.14)*(2) << endl;
      cout << "Area = " << (radius)*(radius)*(3.14) << endl;
      cout << "\nWould you like to do another one? [Y/N]" << endl;
      cin >> response;

   if(response == "Y")
   {
      cout << "\n" << endl;
      goto mainf;
   }

   if(response == "y")
   {
      cout << "\n" << endl;
      goto mainf;
   }

   if(response == "N")
   {
      exit(0);
   }

    if(response == "n")
   {
      exit(0);
   }

   else
   {
        system("cls");
      goto mainf;
   }
}

#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main()
{
double radius;
string response;
int    i;

system("Color 17");

do
   {
   cout << "What is the radius? ";
   cin  >> radius;
   cout << "\nCircumference = " << (radius * 3.14 * 2) << endl;
   cout << "Area = " << (radius * radius * 3.14) << endl;
   cout << "\nWould you like to do another one? [Y/N]" << endl;
   cin  >> response;
   }
while (response == "y" || response == "Y");
}