package main

import (
	"fmt"
)

func main() {
	const (
		add      = "add"
		subtract = "subtract"
		multiply = "multiply"
		divide   = "divide"
		exit     = "exit"
	)

	fmt.Println("Welcome to the Simple Calculator!")
	for {
		var operation string
		fmt.Print("\nEnter operation (add, subtract, multiply, divide, exit): ")
		fmt.Scan(&operation)

		if operation == exit {
			fmt.Println("Goodbye!")
			break
		}

		var num1, num2 float64
		fmt.Print("Enter the first number: ")
		fmt.Scan(&num1)
		fmt.Print("Enter the second number: ")
		fmt.Scan(&num2)

		switch operation {
		case add:
			fmt.Printf("Result: %.2f\n", num1+num2)
		case subtract:
			fmt.Printf("Result: %.2f\n", num1-num2)
		case multiply:
			fmt.Printf("Result: %.2f\n", num1*num2)
		case divide:
			if num2 == 0 {
				fmt.Println("Error: Division by zero is not allowed!")
			} else {
				fmt.Printf("Result: %.2f\n", num1/num2)
			}
		default:
			fmt.Println("Invalid operation. Please try again.")
		}
	}
}