Re: [Boost-users] seed for hash

From: Rares Vernica (rvernica_at_[hidden])
Date: 2007-02-05 12:58:31

OK.

Thank you very much,
Ray

James Dennett wrote:
> Rares Vernica wrote:
>> Hi,
>>
>> Does the hash function uses a seed?
>>
>> If a call:
>> boost::hash<std::string> string_hash;
>> std::size_t h = string_hash("Hash me");
>>
>> and then after a year I call again:
>> string_hash("Hash me");
>>
>> Does it return the same value?
> 
> Yes; a hash is a (pure, deterministic) function of its
> input value, i.e., a function in the mathematical sense
> as well as the C++ sense.  Any hash must satisfy that
> property or algorithms using it will behave in rather
> strange/unpredictable ways.
> 
> -- James