generics/comparable-die/2/die-random.cs - A class Die that implements IComparable<T>.

Lecture 11 - slide 14 : 21 Program 4

using System;

public class Die: IComparable<Die> {
  private int numberOfEyes;
  private Random randomNumberSupplier; 
  private const int maxNumberOfEyes = 6;

  public Die(){
    randomNumberSupplier = Random.Instance();
    numberOfEyes = NewTossHowManyEyes();
  }   

  public int CompareTo(Die other){
    return this.numberOfEyes.CompareTo(other.numberOfEyes);
  }
    
  public void Toss(){
    numberOfEyes = NewTossHowManyEyes();
  }

  private int NewTossHowManyEyes (){
    return randomNumberSupplier.Next(1,maxNumberOfEyes + 1);
  }

  public int NumberOfEyes() {
    return numberOfEyes;
  }

  public override String ToString(){
    return String.Format("[{0}]", numberOfEyes);
  }

}

public class Random {

  // Singleton pattern:
  // Keeps track of unique instance of this class
  private static Random uniqueInstance = null;

  // Holds the instance of System.Random
  private System.Random systemRandom;

  // Singleton pattern: Private constructor.
  private Random(){
    systemRandom = new System.Random(unchecked((int)DateTime.Now.Ticks));
  }

  public static Random Instance(){
    if (uniqueInstance == null)
      uniqueInstance = new Random();
    return uniqueInstance;
  }

  public int Next(int lower, int upper){
    // delegate to systemRandom
    return systemRandom.Next(lower,upper);
  }

}

class App{

  public static void Main(){

    Die[] dice = new Die[]{new Die(), new Die(), new Die(), new Die(),
                           new Die(), new Die(), new Die(), new Die(),
                          };
    Console.WriteLine("Before sorting");
    foreach(Die d in dice)
      Console.Write("{0} ", d);
    
    Console.WriteLine();

    Console.WriteLine("After sorting");
    Array.Sort(dice);
    foreach(Die d in dice)
      Console.Write("{0} ", d);

  }

}