Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
When obtaining the hash code of a string using the GetHashCode() method is there any chance that it can return zero or does the algorithm used guarantee otherwise?
The reason I’m asking is that I have a use case where I need to invent a hash for a null string and I was thinking of using zero rather than hashing some constant string. If I do this how likely am I to get a collision (barring the obvious fact that collisions are always possible)
There’s no way to definitively answer that. The behavior of String.GetHashCode() is documented as being undefined and subject to change between framework versions and to be different between 32bit and 64 bit systems.
If you chose some other value you may be just as likely to have a collision. Zero would be a pretty reasonable default.
The Nullable.GetHashCode() returns 0 if it stores a null value so return a hash code for zero has some precedent.