A C# sets class

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Introduction

A fairly decent sets class based on hashtables and iteration.

Background

Even Google couldn't locate a sets class in C#. So we wrote one.

Below is the Set API

/// Refer to Hashtable constructor documentation.

public Set()
public Set(Set otherSet)
public Set(int capacity)
public Set(Set otherSet, float loadFactor)
public Set(IHashCodeProvider iHashCodeProvider, IComparer iComparer) 
public Set(int capacity, float loadFactor) : base(capacity, loadFactor)
public Set(Set otherSet, IHashCodeProvider iHashCodeProvider, IComparer iComparer) 
public Set(int capacity, IHashCodeProvider iHashCodeProvider, IComparer iComparer) 
public Set(Set otherSet, float loadFactor, IHashCodeProvider iHashCodeProvider, 
           IComparer iComparer) 
public Set(int capacity, float loadFactor, IHashCodeProvider iHashCodeProvider, 
           IComparer iComparer)

//  Adds an item to the set. Items are stored as keys, with no associated values.

public void Add(Object entry)

// Union of set1 and set2.

public static Set operator | (Set set1, Set set2)

// Union of this set and otherSet.

public Set Union(Set otherSet)

// Intersection of set1 and set2.

public static Set operator & (Set set1, Set set2) 

// Intersection of this set and otherSet.

public Set Intersection(Set otherSet) 

// Exclusive-OR of set1 and set2.

public static Set operator ^ (Set set1, Set set2) 

// Exclusive-OR of this set and otherSet.

public Set ExclusiveOr(Set otherSet) 

// The set1 minus set2. This is not associative.

public static Set operator - (Set set1, Set set2) 

// This set minus otherSet. This is not associative.

public Set Difference(Set otherSet) 

Using the code

Below is some self explanatory code that demonstrates the use of this code:

using System;
using System.Collections;

using Extensions;

namespace Extensions.Test
{
    // Unit test for Sets class.

    class Test
    {
        static void DisplayItems(String name, Set theSet) 
        {
            Console.WriteLine(name);
            SortedList sortedItems = new SortedList(CaseInsensitiveComparer.Default);
            foreach(object key in theSet.Keys)
            {
                sortedItems.Add(key, null);
            }
            Console.Write('\t');
            int count = 1;
            foreach(object key in sortedItems.Keys)
            {
                Console.Write(key);
                if (count++ < sortedItems.Keys.Count)
                {
                    Console.Write(", ");
                }
            }
            Console.WriteLine();
        }

        [STAThread]
        static void Main()
        {
            Set setA = new Set(CaseInsensitiveHashCodeProvider.Default, 
                               CaseInsensitiveComparer.Default);
            setA.Add("Green");
            setA.Add("purple");
            setA.Add("Red");
            setA.Add("blue");
            DisplayItems("set A:", setA);

            Set setB = new Set(CaseInsensitiveHashCodeProvider.Default,
                               CaseInsensitiveComparer.Default);
            setB.Add("black");
            setB.Add("Blue");
            setB.Add("green");
            setB.Add("red");
            setB.Add("orange");
            DisplayItems("set B:", setB);

            Set setC = new Set(CaseInsensitiveHashCodeProvider.Default, 
                               CaseInsensitiveComparer.Default);
            setC.Add("pink");
            setC.Add("yellow");
            setC.Add("Black");
            setC.Add("turqoise");
            setC.Add("red");
            DisplayItems("set C:", setC);

            Console.WriteLine("------------------------------------");

            DisplayItems("A union B:", setA.Union(setB));
            DisplayItems("B union C:", setB.Union(setC));
            DisplayItems("A intersect B", setA.Intersection(setB));
            DisplayItems("A xor B:", setA.ExclusiveOr(setB));
            DisplayItems("A xor C:", setA.ExclusiveOr(setC));
            DisplayItems("B xor C:", setB.ExclusiveOr(setC));
            DisplayItems("A - B:", setA.Difference(setB));
            DisplayItems("B - A:", setB.Difference(setA));

            DisplayItems("A union B union C:", setA | setB | setC);
            DisplayItems("B union C union A:", setB | setC | setA);
            DisplayItems("C union B union A:", setC | setB | setA);

            DisplayItems("A intersect B intersect C:", setA & setB & setC);
            DisplayItems("B intersect A intersect C:", setB & setA & setC);

            DisplayItems("(A xor B) xor C:", (setA ^ setB) ^ setC);
            DisplayItems("A xor (B xor C):", setA ^ (setB ^ setC));
            DisplayItems("(C xor A) xor B:", (setC ^ setA) ^ setB);
            DisplayItems("C xor (A xor B):", setC ^ (setA ^ setB));

            DisplayItems("(A - B) - C:", (setA - setB) - setC);
            DisplayItems("A - (B - C):", setA - (setB - setC));
            DisplayItems("(C - B) - A:", (setC - setB) - setA);
            DisplayItems("C - (B - A):", setC - (setB - setA));
        }
    }
}