interface.rb

require_relative 'calculator'
# Calculator (addition)
#
# ask user to enter a number
puts "First number?"
# store first number
first_number = gets.chomp
# check first number class
first_number = checker_to_f(first_number)
# ask user for operation
puts "Operation?"
# store operation
operator = gets.chomp
# check if operator is valid
if ['+', '-', '*', '/'].include?(operator)
  # ask user to enter a second number
  puts "Second number?"
  second_number = gets.chomp
  # check if second number is valid
  second_number = checker_to_f(second_number)
  # display the result
  puts calculator(first_number, second_number, operator)
else
  puts "Operator not found! Try again"
end