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C# Intermediate C# System.Object Object.GetHashCode

Posted by Tiago Ramos
Tiago Ramos
2,380 Points

How can I return a proper hash code?

Hello, I'm trying to return a unique hash code in the GetHashCode() method by multiplying the HashCode of the current object by 31 and then adding it to the new object HashCode.

Can you help me get this rigth?

Thanks a lot :)

VocabularyWord.cs 
using System;

namespace Treehouse.CodeChallenges
{
    public class VocabularyWord
    {
        public string Word { get; private set; }

        public VocabularyWord(string word)
        {
            Word = word;
        }

        public override string ToString()
        {
            return Word;
        }

        public override bool Equals(object obj)
        {
            if(!(obj is VocabularyWord))
            {
                return false;
            }

            var that = obj as VocabularyWord;

            return this.Word.Equals(that.Word);
        }

        public override int GetHashCode(object obj)
        {
            return this.GetHashCode() * 31 + obj.GetHashCode();
        }
    }
}

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

I see two issues at first glance:

  • the "GetHashCode" method should not take any parameters
  • calling a method from inside itself ("this.GetHashCode()") will create a recursion loop