EqualityComparer(T) Class provides a base class for implementations of the IEqualityComparer generic interface. : IComparer « Collections Data Structure « C# / C Sharp

1. C# / C Sharp
2. Collections Data Structure
3. IComparer

EqualityComparer(T) Class provides a base class for implementations of the IEqualityComparer generic interface.

  

using System;
using System.Collections.Generic;

class Program
{
    static Dictionary<Rectangle, String> boxes;

    static void Main(string[] args)
    {

        RectangleSameDimensions boxDim = new RectangleSameDimensions();
        boxes = new Dictionary<Rectangle, string>(boxDim);

        Rectangle redBox = new Rectangle(8, 4);
        Rectangle greenBox = new Rectangle(8, 6);
        Rectangle blueBox = new Rectangle(8, 4);
        Rectangle yellowBox = new Rectangle(8, 8);

        AddBox(redBox, "red");
        AddBox(greenBox, "green");
        AddBox(blueBox, "blue");
        AddBox(yellowBox, "yellow");

        Console.WriteLine();
        Console.WriteLine("Boxes equality by volume:");

        BoxSameVolume boxVolume = new BoxSameVolume();
        boxes = new Dictionary<Rectangle, string>(boxVolume);
        Rectangle pinkBox = new Rectangle(8, 4);
        Rectangle orangeBox = new Rectangle(8, 6);
        Rectangle purpleBox = new Rectangle(4, 8);
        Rectangle brownBox = new Rectangle(8, 8);
        AddBox(pinkBox, "pink");
        AddBox(orangeBox, "orange");
        AddBox(purpleBox, "purple");
        AddBox(brownBox, "brown");
    }

    public static void AddBox(Rectangle bx, string name)
    {
        try
        {
            boxes.Add(bx, name);
            Console.WriteLine("Added {0}, Count = {1}, HashCode = {2}",
                name, boxes.Count.ToString(), bx.GetHashCode());
        }
        catch (ArgumentException)
        {
            Console.WriteLine("A box equal to {0} is already in the collection.", name);
        }




    }
}
public class Rectangle
{
    public Rectangle(int h, int l)
    {
        this.Height = h;
        this.Length = l;
    }
    public int Height { get; set; }
    public int Length { get; set; }
}


class RectangleSameDimensions : EqualityComparer<Rectangle>
{

    public override bool Equals(Rectangle b1, Rectangle b2)
    {
        if (b1.Height == b2.Height & b1.Length == b2.Length)
        {
            return true;
        }
        else
        {
            return false;
        }
    }


    public override int GetHashCode(Rectangle bx)
    {
        int hCode = bx.Height ^ bx.Length;
        return hCode.GetHashCode();
    }

}

class BoxSameVolume : EqualityComparer<Rectangle>
{

    public override bool Equals(Rectangle b1, Rectangle b2)
    {
        if (b1.Height * b1.Length ==
            b2.Height * b2.Length)
        {
            return true;
        }
        else
        {
            return false;
        }
    }


    public override int GetHashCode(Rectangle bx)
    {
        int hCode = bx.Height ^ bx.Length;
        return hCode.GetHashCode();
    }

}

   
    
  

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