Sum of roll of N dice

[Michael Zinn]

Interesting question!

Not sure how to do it quickly for N dice, but you can do it for 2 by using a lookup table for the 36 possible rolls of 2 6 sided dice, i.e. you generate a number between 0 and 35, do a look-up and you are down.

The code might look something like this (the line numbers are important):

Code:


000 - 0
001 - 2
002 - RTN
003 - 0
004 - 3
005 - RTN
006 - 0
007 - 3
008 - RTN
008 - 0
009 - 4
010 - RTN
... [ 4 4 5 5 5 5 6 6 6 6 6 7 7 7 7 7 7 8 8 8 8 8 9 9 9 9 10 10 10 11 11 12 ] ...
...
LBL D
  RAN #
  3
  6
  *
  INT
  3
  *
  CHS
  STO I
  GTO (i)

The "shape" of the lookup table is very regular, so maybe there is an easy way to calculate the distribution directly from the random number.