Building a Better Calculator

num1 = float(input("Enter first number : "))
op = input("Enter operator : ")
num2 = float(input("Enter second number : "))

if op == "+":
  print(num1 + num2)
elif op == "-":
  print(num1 - num2)
elif op == "*":
  print(num1 * num2)
elif op == "/":
  print(num1 / num2)
else:
  print("Invalid operator.")

//Output : Enter first number : 1
//         Enter operator : +
//         Enter second number : 1
//         2.0