factoral.rb

#!/usr/bin/ruby

def factoral(n)
  begin
    if n == 0
      return 1
    elsif n > 0
      return factoral(n - 1) * n
    else n < 0
      abort("Sorry, no negative numbers please")
    end
  rescue
    abort("Sorry, integers only please")
  end
end

puts ""
puts "factoral of 5 if #{factoral(5)}"
#puts "factoral of -5 if #{factoral(-5)}"
puts "factoral of 'c' if #{factoral('c')}"

__END__

factoral of 5 if 120
Sorry, integers only please