Arrays - Randomize an Array

Introduction

Having an array that is sorted is useful but sometimes you need it randomized. For example, if you have a game using a deck of cards it would be required to have the deck shuffled. The demo code below simulates dealing a round of cards in Bridge.

LoadArray()

static void LoadArray(int[] cards, int size)
{
    for (int index = 0; index < size; index++)
    {
        cards[index] = index + 2;
    }
}//end of LoadArray

As the Ace in a suit is the highest card, you need index + 2 to set the correct values in the array.

ShuffleDeck()

Once the array is loaded with sequential numbers, the next step is to randomize the values:

static void ShuffleDeck(int[] cards, int size)
{
    Random random = new Random();
    int swap,
    position1,
    position2;
    for (int index = 0; index < size; index++)
    {
        position1 = random.Next(0, size);
        position2 = random.Next(0, size);
        swap = cards[position1];
        cards[position1] = cards[position2];
        cards[position2] = swap;
    }
}//end of ShuffleDeck

Alternately, you could use nested loops to further randomize the order of the cards.

ShowDeck()

It would be easy to just show the numerical values now ranomized in the array, but as this is a deck of cards it would be better to show the type of card and its suit. The code below does that:

static void ShowDeck(int[] cards, int size)
{
    string suit,
        card;
    int remainder;

    for (int index = 0; index < size; index++)
    {
        if (cards[index] <= 14)
        {
            suit = "C";
        }
        else if (cards[index] <= 27)
        {
            suit = "D";
        }
        else if (cards[index] <= 40)
        {
            suit = "H";
        }
        else
        {
            suit = "S";
        }
        remainder = cards[index] % 13;
        switch (remainder)
        {
            case 1:
                card = "A";
                break;
            case 0:
                card = "K";
                break;
            case 12:
                card = "Q";
                break;
            case 11:
                card = "J";
                break;
            default:
                card = remainder.ToString();
                break;
        }
        Console.Write($"{card} {suit}\t");
     }
     Console.WriteLine();
 }//end of ShowDeck

Program Class - Part 1

At this point you need the following code in the Main() method:

static void Main(string[] args)
{
    Setup();
    const int PhysicalSize = 52;
    const int HandSize = 13;
    int[] cards = new int[PhysicalSize];
    int[] west = new int[HandSize];
    int[] north = new int[HandSize];
    int[] east = new int[HandSize];
    int[] south = new int[HandSize];

    LoadArray(cards, PhysicalSize);

    Console.WriteLine("Original Array:");
    ShowDeck(cards, PhysicalSize);

    Console.WriteLine("\nRandomized Array:");
    ShuffleDeck(cards, PhysicalSize);
    ShowDeck(cards, PhysicalSize);

    Console.ReadLine();
}//eom

static void Setup()
{
    Console.Title = "Randomize Array Demo";
    Console.ForegroundColor = ConsoleColor.Black;
    Console.BackgroundColor = ConsoleColor.White;
    Console.Clear();
}//end of Setup

There are 4 arrays, one for each player’s hand, that will be used later. At this point you should have something like:

DealDeck()

In this method all that is done is take the shuffled deck and add cards to each player:

static void DealDeck(int[] cards, int[] west, int[] north, int[] east, int[] south, int deckSize)
{
    int index = 0,
    handIndex = 0;
    while(index < deckSize)
    {
        west[handIndex] = cards[index];
        north[handIndex] = cards[index + 1];
        east[handIndex] = cards[index + 2];
        south[handIndex] = cards[index + 3];
        index += 4;
        handIndex++;
    }
}//end of DealDeck

Program Class - Part 2

You will need to add the following code in the Main() method below what is already there:

//deal the cards to each player
DealDeck(cards, west, north, east, south, PhysicalSize);
Console.WriteLine("\nWest's Hand");
ShowDeck(west, HandSize);
Console.WriteLine("\nNorth's Hand");
ShowDeck(north, HandSize);
Console.WriteLine("\nEast's Hand");
ShowDeck(east,HandSize);
Console.WriteLine("\nSouth's Hand");
ShowDeck(south, HandSize);

Note: this code call the ShowDeck() method but instead of passing is the entire deck, you pass in each player’s hand.

At this point the output should look something like:

Options

The following options could be made to this program:

• Instead of letters for the suits, use the suit chracters
• Colour the Diamond and Heart suits red
• Sort each player’s hand by suit and card value descending
• Add code to add the player’s points:
  • Ace = 4
  • King = 3
  • Quenn = 2
  • Jack = 1

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