Task

(Given an equal-probability generator of one of the integers 1 to 5
as dice5),   create dice7 that generates a pseudo-random integer from
1 to 7 in equal probability using only dice5 as a source of random
numbers,   and check the distribution for at least one million calls using the function created in   Simple Random Distribution Checker.


Implementation suggestion:
dice7 might call dice5 twice, re-call if four of the 25
combinations are given, otherwise split the other 21 combinations
into 7 groups of three, and return the group index from the rolls.

(Task adapted from an answer here)

require './distcheck.rb'
 
def d5
  1 + rand(5)
end
 
def d7
  loop do
    d55 = 5*d5 + d5 - 6
    return (d55 % 7 + 1) if d55 < 21
  end
end
 
distcheck(1_000_000) {d5}
distcheck(1_000_000) {d7}