what happens if I skip implementing GetHashCode

[Tony]

Hello!

Here I have a Card class with several methods.

Now to my question I don't really fully understand what purpose this
GetHashCode is used for.
That's why I bring it up again.
In this simple example below with the Card class what would happen if I skip
this GetHashCode in this Card class?
Is it possible to write some simple test program to prove that this
GetHashCode will prevent
error or problem to occur?

class Card
{
//rank and suit are defined here
public static bool operator==(Card card1, Card card2)
{
return card1.suit == card2.suit) && (card1.rank==ca rd2.rank);
}

public override bool Equals(object card)
{
return this == (Card) card;
}

public override int HetHashCode()
{
return 13*(int)rank + (int)suit;
}
....
....
}

//Tony

[Peter Duniho]

On Fri, 13 Jun 2008 01:51:10 -0700, Tony <jo************ *****@telia.com >
wrote:

Well it's not possible to add two key that are the same to a hashtable.
Have I missed something here?

Yes. You keep thinking that you are talking about "two key that are the
same". But that's the point: if the hash code is different, the two keys
aren't the same. Even if the Equals() method says they are.

Pete