C#•4y ago

What's the meaning of CS0659?

'class' overrides Object.Equals(object o) but does not override Object.GetHashCode()

'class' overrides Object.Equals(object o) but does not override Object.GetHashCode()

'class' overrides Object.Equals(object o) but does not override Object.GetHashCode()

'class' overrides Object.Equals(object o) but does not override Object.GetHashCode()

I got this warning message but i cannot find what's the reason I should override GetHashCode. Also, how should I implement it?