How do I describe all integers in Ruby - ruby

Question

I'm trying to write a basic program that spits out the English version of a number when the user inputs a numeral:
input = 44
output = fourty four
Is there a way to describe all integers?
Basically I want the execution to look something like:
number = gets.chomp
if number != (whatever the nomenclature is for integer)
puts 'Please enter a positive number'
or something to that effect.

Answer 1

You can do that with the numbers_and_words gem:
https://github.com/kslazarev/numbers_and_words
It supports languages other than english as well.
For example:
21.to_words
=> "twenty-one"
44.to_words
=> "forty-four"

Answer 2

I modified the Fixnum class and added a method in_words. What I did is I broke each number up into groups of three, so 100000 turns into [100, 000] and 123456789 turns into [123, 456, 789] or 1543 turns into [1, 453] then I went element by element and named every number in the element and added the appropriate word, like hundred and thousand. If you have any questions I am happy to explain!
class Fixnum
LOW = %w(zero one two three four five six seven
eight nine ten eleven twelve thirteen fourteen
fifteen sixteen seventeen eighteen nineteen)
TWO_DIGIT = %w(ten twenty thirty forty fifty sixty seventy eighty ninety)
BIG_NUMS = %w(hundred thousand million billion trillion)
def in_words
# Break up number into bytes with three bits each
# Then turn each byte into words
# Break into bytes
number = self.to_s.reverse
bytes = []
num_bytes = (number.length.to_f / 3.0).ceil()
num_bytes.times { |x| bytes << number[(x*3)..(x*3)+2].reverse }
#puts bytes.reverse.join(",")
# Turn bytes into words bit by bit
word = []
text = ""
bytes.each_with_index do |byte, i|
text = ""
# First bit
text = LOW[byte[0].to_i] if (byte.length == 3 && byte[0].to_i != 0) || byte.length == 1
# Add hundred if 3 bits
text += " hundred" if byte.length == 3 && byte[0].to_i != 0
# Second bit
if byte.length == 3 # Three bits
if byte[1].to_i > 1 # Second bit greater than teens
text += " " + TWO_DIGIT[byte[1].to_i + (-1)]
elsif byte[1].to_i != 0 # Second bit not zero
text += " " + LOW[byte[1..2].to_i]
end
elsif byte.length == 2 # Two bits
if byte[0].to_i > 1 # Greater than teens
text += " " + TWO_DIGIT[byte[0].to_i + (-1)]
text += " " + LOW[byte[1].to_i] if byte[1].to_i != 0
else # Less than twenty
text += LOW[byte[0..1].to_i]
end
end
# Third bit if three bytes and second bit > teens and third bit nonzero
text += " " + LOW[byte[2].to_i] if byte[1].to_i != 1 && byte[2].to_i > 0 && byte.length > 2
# Add trillion/billion/million/thousand
text += " " + BIG_NUMS[i] if i != 0 && byte.to_i != 0
word << text.strip if text.strip != ""
end
word.reverse.join(" ")
end
end
Because I modified the Fixnum object, you can call this from any Fixnum e.g. 44.in_words
EDIT: It looks like you might be trying to check input for integers. I would recommend making a function to handle that:
def check_input(i)
if !(i =~ /^[0-9]+$/)
puts "Sorry, that is an invalid input! Please try again"
i = check_input(gets.chomp)
end
i.to_i
end
I think the best way to handle that is with regex (pattern matching). Basically your function checks if the input isn't a number, then it asks for input again. If it is a number, then the function returns the number. /^[0-9]+$/ is the regex. ^ means start of the line and $ means end of the line. [0-9] matches any digit zero through nine (as the Tin Man commented, you can also use \d to represent any digit and it is equivalent), and + means match the previous thing (any digit) at least once.