OS/2 Shareware BBS: 10 Tools/10-Tools.zip/rbemx144.zip/ruby-1.4.4/sample/sieve.rb

Text File | 1999-08-13 | 244b | 15 lines

# sieve of Eratosthenes
max = Integer(ARGV.shift || 100)
sieve = []
for i in 2 .. max
  sieve[i] = i
end

for i in 2 .. Math.sqrt(max)
  next unless sieve[i]
  (i*i).step(max, i) do |j|
    sieve[j] = nil
  end
end
puts sieve.compact.join ", "