while(diameterInputLoop == false)
{
/***********************************************************************************************
 * Initialize the Scanner in at the beginning of the loop
 * because invalid inputs will close the scanner to clear it
***********************************************************************************************/
  Scanner in = new Scanner(System.in);

/***********************************************************************************************
 * Prompt for Diameter
***********************************************************************************************/
  System.out.print("Enter the jelly bean diameter in cm: ");

/***********************************************************************************************
 * If statement to verify if a number was entered
 * with a nested if statement to check if the value is less than or equal to zero
 * If no number is entered, repeat the input loop
***********************************************************************************************/
  if(in.hasNextDouble())
  {//start valid number if statement
    jellyBeanDiameter = in.nextDouble();
    //set controller to true, exiting loop
    diameterInputLoop = true;

    // check for positive numbers
    if(jellyBeanDiameter > 0 )
    {
      //if diameter is positive, set loop controller to true to exit loop
      diameterInputLoop = true;
    }

    //if a negative number is entered
    else
    {//start negative  check

      //print error for negative & 0 numbers
      System.out.println("Error: invalid input, diameter must be a number greater than zero");

      //close scanner
      in.close();

      //reset diameter value
      jellyBeanDiameter = 1.0;

      //set controller to false to repeat loop
      diameterInputLoop = false;

    }//end negative if check{

  }//end valid number if statement

  //if a number was not entered
  else
  {
    //print error asking for number
    System.out.println("Error: invalid input, diameter must be a number.");

   //close scanner
    in.close();

    //reset diameter value
    jellyBeanDiameter = 1.0;

    //set controller to false telling loop to repeat
    diameterInputLoop = false;

  }//end else

}//end while loop