8.5.1EnglishNum.rb

def englishNumber number
	if number < 0 # No negative numbers
	  return 'Please enter a number zero or greater.'
	end
	if number == 0
	  return 'zero'
	end
	
	numString = '' # This is the returned String
	
	onesPlace = ['one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine']
	tensPlace = ['ten', 'twenty', 'thirty', 'fourty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety']
	teenagers = ['eleven', 'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen']
	
	#left is how much of the nubmer we still have left to write out.
	#"write" is the parte we are writing out right now.
  #trillions
  left = number
  write = left / 1000000000000
  left = left - write * 1000000000000
  
  if write > 0
    trillions = englishNumber write
    numString = numString + trillions + ' trillion '
    
    if left > 0
      numString = numString + ' '
    end
  end
  	
  #billions 
  write = left / 1000000000
  left = left - write * 1000000000
  
  if write > 0
    billions = englishNumber write
    numString = numString + billions + ' billion '
    
    if left > 0
      numString = numString + ' '
    end
  end
  
  #millions
  write = left / 1000000
  left = left - write * 1000000
  
  if write > 0
    millions = englishNumber write
    numString = numString + millions + ' million '
    
    if left > 0
      numString = numString + ' '
    end
  end

  #thousands
  write = left / 1000
  left = left - write * 1000
  
  if write > 0
    thousands = englishNumber write
    numString = numString + thousands + ' thousand '
    
    if left > 0
      numString = numString + ' '
    end
  end
  
  #hundreds
  write = left / 100
  left = left - write * 100
  
  if write > 0
    hundreds = englishNumber write
    numString = numString + hundreds + ' hundred '
    
    if left > 0
      numString = numString + ' '
    end
  end
  
  #tens
  write = left / 10
  left = left - write * 10
  
  if write > 0
    if ((write == 1) && (left > 0))
      numString = numString + teenagers[left - 1]
      left = 0
    else
      numString = numString + tensPlace[write - 1]
    end
    
    if left > 0
      numString = numString + '-'
    end
  end
  
  write = left
  left = 0
  
  if write > 0
    numString = numString + onesPlace[write - 1]
  end
  
  numString
end

puts englishNumber(  0)
puts englishNumber(  9)
puts englishNumber( 10)
puts englishNumber( 11)
puts englishNumber( 17)
puts englishNumber( 32)
puts englishNumber( 88)
puts englishNumber( 99)
puts englishNumber(100)
puts englishNumber(101)
puts englishNumber(234)
puts englishNumber(3211)
puts englishNumber(99999)
puts englishNumber(100000000000)