Calculates the probability rates for a Nd10 throw using a World of Darkness system for successes/failures

d10.rb

min_to_succ = 6

puts 'How many d10 should be rolled?'
n = gets.chomp.to_i

comb = (1..10).to_a.map { |x| [x] }

for i in 2..n
  comb2 = []
  for j in 1..10
    for k in 0...comb.length
      comb2 << (comb[k] + [j])
    end
  end
  comb = comb2
end

succ = [0]*(2*n+1)

comb.each do |x|
  s = 0
  x.each do |y|
    s += (y >= min_to_succ ? 1 : (y == 1 ? -1 : 0))
  end
  succ[n+s] += 1
end

sum = succ.reduce(:+).to_f
succ.each_with_index do |x, i|
  s = i - n
  puts "Results with %d %s: \t%0.3g%%" % [ s.abs, (s < 0 ? 'fails' : 'succ.'),  x/sum*100]
end

puts "Failed results: \t%0.3g%%" % [ succ[0...n].reduce(:+) / sum * 100 ]
puts "Unsuccessful results \t%0.3g%%" % [ succ[n] / sum * 100 ]
puts "Successful results: \t%0.3g%%" % [ succ.drop(n+1).reduce(:+) / sum * 100 ]