Add hamming in C#

Author: lynnvfrank

hamming/Example.cs

@@ -0,0 +1,38 @@
+using System;
+
+public class Hamming
+{
+    public static int Compute (string firstStrand, string secondStrand)
+    {
+        return new Hamming(firstStrand,secondStrand).Distance();
+    }
+
+    private string firstStrand;
+    private string secondStrand;
+
+    public Hamming (string firstStrand, string secondStrand)
+    {
+        this.firstStrand = firstStrand;
+        this.secondStrand = secondStrand;
+    }
+
+    public int Distance ()
+    {
+        char[] firstStrandChars = firstStrand.ToCharArray();
+        char[] secondStrandChars = secondStrand.ToCharArray();
+
+        int difference = 0;
+
+        for (int i = 0; i < CommonDistance(); i++)
+        {
+            if (firstStrandChars[i] != secondStrandChars[i]) { difference++; }
+        }
+
+        return difference;
+    }
+
+    private int CommonDistance ()
+    {
+        return Math.Min(firstStrand.Length,secondStrand.Length);
+    }
+}

hamming/HammingTest.cs

@@ -0,0 +1,53 @@
+using NUnit.Framework;
+
+[TestFixture]
+public class HammingTest
+{
+    [Test]
+    public void NoDifferenceBetweenEmptyStrands ()
+    {
+        Assert.AreEqual(0,Hamming.Compute("",""));
+    }
+
+    [Test]
+    public void NoDifferenceBetweenIdenticalStrands ()
+    {
+        Assert.AreEqual(0,Hamming.Compute("GGACTGA","GGACTGA"));
+    }
+
+    [Test]
+    public void CompleteHammingDistanceInSmallStrand ()
+    {
+        Assert.AreEqual(3,Hamming.Compute("ACT","GGA"));
+    }
+
+    [Test]
+    public void HammingDistanceInOffByOneStrand ()
+    {
+        Assert.AreEqual(9,Hamming.Compute("GGACGGATTCTG","AGGACGGATTCT"));
+    }
+
+    [Test]
+    public void SmallingHammingDistanceInMiddleSomewhere ()
+    {
+        Assert.AreEqual(1,Hamming.Compute("GGACG","GGTCG"));
+    }
+
+    [Test]
+    public void LargerDistance ()
+    {
+        Assert.AreEqual(2,Hamming.Compute("ACCAGGG","ACTATGG"));
+    }
+
+    [Test]
+    public void IgnoresExtraLengthOnOtherStrandWhenLonger ()
+    {
+        Assert.AreEqual(3,Hamming.Compute("AAACTAGGGG","AGGCTAGCGGTAGGAC"));
+    }
+
+    [Test]
+    public void IgnoresExtraLengthOnOriginalStrandWhenLonger ()
+    {
+        Assert.AreEqual(5,Hamming.Compute("GACTACGGACAGGGTAGGGAAT","GACATCGCACACC"));
+    }
+}