title: Size of the hash table
body: <p>Let the size of the hash table to be static (I set it once). I want to set it according to the number of entries. Searching yielded that the size should be a prime number and equal to 2*N (the closest prime number I guess), where N is the number of entries.</p>
  
  <p>For simplicity, assume that the hash table will not accept any new entries and won't delete any.</p>
  
  <p>The number of entries will be 200, 2000, 20000 and 2000000.</p>
  
  <p>However, setting the size to 2*N seems too much to me. It isn't? Why? If it is, which is the size I should pick?</p>
  
  <p>I understand that we would like to avoid collisions. Also I understand that maybe there is no such thing as ideal size for the hash table, but I am looking for a starting point.</p>
  
  <p>I using C and I want to build my own structure, for educating myself.</p>