O1. ComputerStore / O1. Mid Exam Retake

package MidExam.O1;

import java.util.Scanner;

public class O1ComputerStore {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String command = scanner.nextLine();
        double sum = 0;
        while (command.length() < 7) {
            double product = Double.parseDouble(command);
            if (product == 0) {
                System.out.println("Invalid order!");
            } else if (product < 0) {
                System.out.println("Invalid price!");
            } else {
                sum += product;
            }
            command = scanner.nextLine();
        }
        if (command.equals("regular") && sum <= 0 || command.equals("special") && sum <= 0) {
            System.out.println("Invalid order!");
        } else {
            System.out.println("Congratulations you've just bought a new computer!");
            System.out.printf("Price without taxes: %.2f$%n", sum);

            double taxes = sum * 1.2 - sum;
            double totalPrice = sum + taxes;
            if (command.equals("special")) {
                totalPrice = totalPrice * 0.90;
            }
            System.out.printf("Taxes: %.2f$%n", taxes);
            System.out.println("-----------");
            System.out.printf("Total price: %.2f$", totalPrice);
        }
    }
}