Ruby学習#19 Building a Better Calculator

puts "Enter first number: "
num1 = gets.chomp().to_f
puts "Enter operator: "
op = gets.chomp()
puts "Enter second number: "
num2 = gets.chomp().to_f

if op == "+"
puts (num1 + num2)
elsif op == "-"
puts (num1 - num2)
elsif op == "/"
puts (num1 / num2)
elsif op == "*"
puts (num1 * num2)
else
puts "invalid operator"

end