17. Another Scanner hasNextDouble example

• A method that gets a valid numeric format

  
  public static double getDouble(Scanner sc, String prompt)
  {
      double dbl = 0.0;
      boolean isValid = false;
      while (isValid == false)
      {
          System.out.print(prompt);
          if (sc.hasNextDouble())
          {
              dbl = sc.nextDouble();
              isValid = true;
          }
          else
          {
              System.out.println(
                  "Error! Invalid number. Try again.");
          }
          sc.nextLine();       // discard any other data
      }
      return dbl;
  }