Ive found loads of examples of double hashing all of the examples tell me that you have to use %5 when you hash the 2nd time.
My question is why 5? is it an agreement that you always use 5 or how does it work?
one example: https://www.cs.washington.edu/education/courses/326/00wi/handouts/lecture16/sld025.htm
In a hash table with N places, the idea is to use two independent hash functions h1(key) and h2(key) and then use the probing sequence
h1 % N, (h1 + h2) % N, (h1 + 2*h2) % N, (h1 + 3*h2) % N, ...
You want to make sure that the the greatest common divisor of h2 and N is 1, otherwise you do not reach all places in the table.
there are several schemes this can be achieved, for example: