Question

I have an immutable class whose only field is a bool[] (size determined at runtime).

How can I compute a good hash code of this class? Generally I would just call GetHashCode() on each field, and combine them with one of these operators: + | &, but since the only possible hash codes are 0 for false and 1 for true, that’s not really going to get me anywhere. My implementation needs to work with only bools, and must work for an arbitrary-sized array.

(Probably doesn’t matter much, but I’m coding in C#/.NET.)

Answer 1

Assuming your bool[] is named bools:

unchecked { 
    int hash = 17;
    for(int index = 0; index < bools.Length; index++) {
        hash = hash * 23 + bools[index].GetHashCode();
    }
    return hash;
}