Question

Basically i am using the hasCode() from the Objects class to obtain a hash code of some strings.

I want that number to represent a position in the array. Basically a hash table.
I havent written code for this yet.

I had in mind:

 int hashNumber = SomeString.hascode(), pos; 
 String array[] = new String[10];

 if (hashNumber > 0)
   pos = hashNumber % array.length
 if (hasNumber < 0 )
   //dont know what to do

I do know for a fact that hashCode can return a negative integer.
What to do if its negative integer?
i though about adding the array length

  pos = hashNumber + array.length

is this the best way?

thanks in advance

Answer 1

If hashNumber is negative, just get the mod of -hashNumber (which will be positive):

if (hashNumber >= 0)
  pos = hashNumber % array.length
else
  pos = -hashNumber % array.length

Or for a single expression that will work for both:

pos = (hashNumber % array.length + array.length) % array.length

See this answer to a question about Java’s behavior with mod and negative numbers.