What is an appropriate `GetHashCode()` algorithm for a 2D point struct (avoiding clashes)

Question

Consider the following code:

struct Vec2 : IEquatable
{
    double X,Y;

    public bool Equals(Vec2 other)
    {
        return X.Equals(other.X         


        

Answer 1

Jon skeet has this covered:

What is the best algorithm for an overridden System.Object.GetHashCode?

   public override int GetHashCode()
   {
       unchecked // Overflow is fine, just wrap
       {
           int hash = 17;
           // Suitable nullity checks etc, of course :)
           hash = hash * 23 + X.GetHashCode();
           hash = hash * 23 + Y.GetHashCode();
           return hash;
       }
   }

Also, change your Equals(object) implementation to:

return Equals(obj as FVector2);

Note however that this could perceive a derived type to be equal. If you don't want that, you'd have to compare the runtime type other.GetType() with typeof(FVector2) (and don't forget nullity checks) Thanks for pointing out it's a struct, LukH

Resharper has nice code generation for equality and hash code, so if you have resharper you can let it do its thing