/**
 * This is the basis for the third task in Lab 12,
 * Applications. The task is to count the different
 * kinds of numbers. The numbers between zero and
 * nine, inclusive, are divided into the following
 * categories:
 * <li>Identity - the additive identity element, zero;
 * and the multiplicative identity element, one.
 * <li>Prime - a number that can only be evenly divided
 * by itself and one.
 * <li>Composite - a number that is the product of primes,
 * two or more, not necessarily different prime numbers.
 * </ul>
 * The numbers outside of the range 0-9 will simply
 * be counted as other.test.
 * <p>
 * You might recognize this as an adaptation of the example
 * showing how to write a switch statement. This now has
 * been updated to include user input, using Scanner.
 */
public class CountNumbers {

  /**
  * The application method
  */
  public static void main(String[] args) {
  CountNumbers numbers = new CountNumbers();
  System.out.println("Please enter an integer:");

   // Checking for an integer
    if (numbers.in.hasNextInt()) {
      // Read the input
      int input = numbers.in.nextInt();
      numbers.switchCounter(input);
    }
    else  {
       // Clear scanner if it was not an integer and give an error
       numbers.in.next();
       System.err.println("Non-integer input ignored.");
    }
    numbers.printSummary();
  }

  // The fields to keep track of the counts
  private int identity;
  private int prime;
  private int composite;
  private int other;

  // The scanner
  private java.util.Scanner in;

  /**
   * The constructor initializes the fields.
   */
  public CountNumbers() {
    identity = 0;
    prime = 0;
    composite = 0;
    other = 0;
    in = new java.util.Scanner(System.in);
  }

  /**
   * This is the switch version of the counting routine.
   * @param input The value read from the user input
   */
  public void switchCounter(int input) {
    // the switch statement, based on the int value input
    switch(input) {
      // count the identity elements: 0 and 1
      case 1:
      case 0:
        identity ++;
        break;
      // count the prime numbers
      case 2:
      case 3:
      case 5:
      case 7:
        prime ++;
        break;
      // count the composite numbers
      case 4:
      case 6:
      case 8:
      case 9:
        composite ++;
        break;
    }
  }

  /**
   * Print out the summary statistics, the counts.
   */
  public void printSummary() {
    System.out.println();
    System.out.println("Here are the counts:");
    System.out.println("   " + identity + " identity elements");
    System.out.println("   " + prime + " prime numbers");
    System.out.println("   " + composite + " composite numbers");
    System.out.println("   " + other + " values out of range");
  }

}