#!/usr/bin/ruby

$a = 8e-4
$k = 10.0

def es(t)
  6.11 * 10 ** (7.5 * t / (t + 237.3))
end

def ew(t, ttw)
  tw = t - ttw
  es(tw) - $a * 1013.24 * ttw
end

def rh(t, ttw)
  e = ew(t, ttw)
  e / es(t)
end

ts = (0..10).to_a.map{|i| 40.0 - 5.0 * i}
ttws = (0..20).to_a.map{|i| 0.5 * i}
for t in ts
  as = ttws.map{|ttw|
    ' %3.0f' % (100.0 * rh(t, ttw))
  }
  as.unshift('%3.0f: ', t)
  puts as.join
end