Time in Words (Ruby)

TimeinWords.rb

def get_word(num)
	teen = "teen"
	case num
	when 0;	return "o' clock"
	when 1;	return "one"
	when 2;	return "two"
	when 3;	return "three"
	when 4;	return "four"
	when 5; return "five"
	when 6; return "six"
	when 7; return "seven"
	when 8; return "eight"
	when 9; return "nine"
	when 10; return "ten"
	when 11; return "eleven"
	when 12; return "twelve"
	when 13; return "thirteen"
	when 14,16,17,19; return get_word(num.to_s[1].to_i)+teen
	when 15; return "fif"+teen
	when 18; return "eigh"+teen
	when 20; return "twenty"
	when 21..29; return get_word(20)+ " " + get_word(num.to_s[1].to_i)
	else return "NaN"
	end
end

def time_in_words(h,m)
	case m 
	when 0; return "#{get_word(h)} #{get_word(m)}"
	when 1; return "#{get_word(m)} minute past #{get_word(h)}"
	when 2...15; return "#{get_word(m)} minutes past #{get_word(h)}"
	when 15; return "quarter past #{get_word(h)}"
	when 16...30; return "#{get_word(m)} minutes past #{get_word(h)}"
	when 30; return "half past #{get_word(h)}"
	when 31...45; return "#{get_word(60-m)} minutes to #{get_word(h+1)}"
	when 45; return "quarter to #{get_word(h+1)}"
	when 46...60; return "#{get_word(60-m)} minutes to #{get_word(h+1)}"
	else return "NaN"
	end
end

#read in hour and minute from STDIN
h = gets.chomp.to_i
m = gets.chomp.to_i
puts time_in_words(h,m)