calculator.rb

require 'io/console'

def read_char
  STDIN.echo = false
  STDIN.raw!

  input = STDIN.getc.chr
  if input == "\e" then
    input << STDIN.read_nonblock(3) rescue nil
    input << STDIN.read_nonblock(2) rescue nil
  end
ensure
  STDIN.echo = true
  STDIN.cooked!

  return input
end

def perform_calculation(num1, op, num2)
   num1.to_f.send(op, num2.to_f)
end

def is_numeric?(user_input)
  user_input.to_i.to_s == user_input || user_input.to_f.to_s == user_input
end

def say(message)
  puts "=>#{message}"
end

puts "A simple calculator which can perform addition, subtraction, and multiplication
on two values: "
puts "Values can include positives, negatives, and decimals"

def get_input(instance)
  begin
    puts "Enter your #{instance} value: "
    value = gets.chomp
  end until is_numeric?(value)
  return value
end

value_1 = get_input("first")
value_2 = get_input("second")

puts "Enter a valid operator to perform a calculation (+ - or *): Press Control-C to quit"

def collect_operator(num_1,num_2)
  case read_char
  when "\-"
    operator = "-"
    puts operator
    say "#{perform_calculation(num_1,operator,num_2)}"
  when "\+"
    operator = "+"
    puts operator
    say "#{perform_calculation(num_1,operator,num_2)}"
  when "\*"
    operator = "*"
    puts operator
    say "#{perform_calculation(num_1,operator,num_2)}"
  when "\u0003"
    puts "CONTROL-C"
    exit 0
  else
    nil
  end
end

collect_operator(value_1,value_2) while(true)