; ожидаемая ошибка в заголовке метода

Question

Я знаю, что в заголовках методов вы не должны заканчивать его точкой с запятой; однако, все мои заголовки метода показывают ту же ошибку:; ожидается. Это для конца заголовка, а также между двумя параметрами. Как бы я это исправить?

    import java.util.Scanner;

    import java.text.DecimalFormat;

    // This program will calculate the cost of someone's order at a coffee shop with applied possible  discounts and tax

    public class CoffeeShopWithMethods
    {
      public static void main (String [] args)
      {

        double cost = 0;
        double discount = 0; 

        // Scanner allows user to enter values
        Scanner user_input = new Scanner(System.in);
        String username;
        System.out.print("\nEnter your username: ");
        username = user_input.next( );
        System.out.print ("\nWelcome to Casey's Classic Coffee, " + username + "! \n");

        //call methods
        displayMenu();
        displayOutput(cost, discount, Discounted_cost, tax, Total_cost);

        System.out.println("\nThank you " + username + "! Have a nice day!");
    }

    //outputs the menu to the screen
    public static void displayMenu()
    {
        System.out.println ("\n\tItem\t\tCost\n\t1. Coffee\t$1.50\n\t2. Latte\t$3.50\n\t3. Cappuccino\t$3.25\n\t4. Espresso\t$2.00");
    }

    //prompts the user to enter item number, returns user input
    public static int getItemNumber(int number) //error: ; expected
    {
        int number;
        Scanner number = new Scanner(System.in);
        System.out.print ("\nPlease enter the desired item number: ");
        number = user_input.nextInt();
        return number;
    }

    //prompts user to enter quantity, returns user input
    public static int getQuantity (int quantity) //error: ; expected
    {
        System.out.print ("\nPlease enter the quantity: ");
        quantity = user_input.nextInt(); 
        return quanity; 
    }

    //takes the item number and quantity and returns the subtotal
    public static double computeSubTotal (double cost) //error: ; expected
    {
        int number = getItemNumber(number);
        int quantity = getQuantity(quantity);

        // Used final double in order to make coffee shop items constant
        final double COFFEE = 1.50;
        final double LATTE = 3.50;
        final double CAPPUCCINO = 3.25;
        final double ESPRESSO = 2.00;

        double cost = 0;

        if (number == 1)
            cost = quantity * COFFEE;
        else if (number == 2)
            cost = quantity * LATTE;
        else if (number == 3)
            cost = quantity * CAPPUCCINO;
        else if (number == 4)
            cost = quantity * ESPRESSO;
    }

    //takes the subtotal and returns true if the user earned a discount; otherwise, returns false
    public static boolean discountCheck (double cost) //error: ; expected
    {
        boolean status;

        if (cost >= 10)
            {
            status = true;
            }
        else if (cost < 10)
            {
            status = false;
            }
        return status;
    }

    //takes the subtotal and returns the dollar amount of the discount earned by the user
    public static double computeDiscount (double cost, double discount) //error: ; expected
    {
        if (discountCheck() == true)
        {
            discount = cost * 0.10;

        }
        else if (discountCheck() != true)
        {
            discount = 0;

        }
        return discount;

    }

    //takes the subtotal and the discount amount and returns the price after the discount is applied
    public static double computePriceAfterDiscount (double cost, double discount) //error: ; expected
    {
        double discount = 0; 
        double Discounted_cost = 0;

        Discounted_cost = cost - discount;
        return Discounted_cost; 
    }

    //takes the prices after the discount is applied and tax rate and returns the tax amount
    public static double computeTax(double Discounted_cost) //error: ; expected
    {
        tax = Discounted_cost * 0.07;
        return tax;
    }

    //takes the price after the discount is applied and the tax amount and returns the final total
    public static double computeTotal(double Discounted_cost, double tax) //says ; expected
    {
        Total_cost = Discounted_cost + tax;
        return Total_cost;
    }

    //takes the subtotal, discount amount, price after discount, tax, and final total and displays all the lines of output to the user
    public static void displayOutput(double cost, double discount, double Discounted_cost, double tax, double Total_cost) //says ; expected at the end of method header
    {
        //call methods
        double cost = computeSubTotal(cost);
        double discount = computeDiscount(cost, discount);
        double Discounted_cost = computePriceAfterDiscount(cost, discount);
        double tax = computeTax(Discounted_cost);
        double Total_cost = computeTotal(Discounted_cost, tax);

        System.out.printf ("\nTotal before discount and tax: $%.2f\n ", cost);

        System.out.printf("\nCalculated discount: $%.2f\n", discount);
        System.out.printf("\nTotal after special discount: $%.2f\n", Discounted_cost);

        System.out.printf("\nTax: $%.2f\n", tax); 
        System.out.printf ("\nTotal cost: $%.2f\n", Total_cost);
    }
} //error:reached end of the file while parsing

Answer 1

Вот весь ваш код исправлен и работает: http://ideone.com/ta0R21 Я действительно рекомендую изменить его. Я предлагаю использовать глобальные переменные в некоторых случаях. словно Scanner объект. Вместо инициализации нового Scanner каждый вызов метода, используйте глобальный для обработки всей работы

Answer 2

1) Вы используете переменные без объявления: например, сравните этот фрагмент с вашим фрагментом кода.

public static double computeTotal(double Discounted_cost, double tax)
    {
        double Total_cost = Discounted_cost + tax;
        return Total_cost;
    }

2) Вы вызываете неопределенные методы. Например: вы вызываете discountCheck(), но вы определили это так. и вы не инициализировали локальные переменные перед использованием

public static boolean discountCheck (double cost){
        boolean status;

        if (cost >= 10)
        {
            status = true;
        }
        else if (cost < 10)
        {
            status = false;
        }
        return status;
    }

в вышеприведенном методе статус должен быть инициализирован.

3) Вы объявляете дубликаты переменных, которые уже доступны для методов через параметры. увидеть код, определенный вами здесь:

public static void displayOutput(double cost, double discount, double Discounted_cost, double tax, double Total_cost)
    {
        //call methods
        double cost = computeSubTotal(cost);
        double discount = computeDiscount(cost, discount);
        double Discounted_cost = computePriceAfterDiscount(cost, discount);
        double tax = computeTax(Discounted_cost);
        double Total_cost = computeTotal(Discounted_cost, tax);

        System.out.printf ("\nTotal before discount and tax: $%.2f\n ", cost);

        System.out.printf("\nCalculated discount: $%.2f\n", discount);
        System.out.printf("\nTotal after special discount: $%.2f\n", Discounted_cost);

        System.out.printf("\nTax: $%.2f\n", tax); 
        System.out.printf ("\nTotal cost: $%.2f\n", Total_cost);
    }

Answer 3

Я бы начал с извлечения вашего MenuItem(s) в enum лайк,

static enum MenuItem {
    COFFEE("Coffee", 1.5), LATTE("Latte", 3.5), CAPPUCINO("Cappuccino",
            3.25), ESPRESSO("Espresso", 2);
    MenuItem(String name, double cost) {
        this.name = name;
        this.cost = cost;
    }

    double cost;
    String name;

    public String toString() {
        return String.format("%s $%.2f", name, cost);
    }
}

Тогда ваши ошибки компилятора были в основном из-за объявления повторяющихся имен локальных переменных. Я смог исправить ошибки компилятора и создать нечто, похожее на то, что вы хотите,

public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    System.out.println("Enter your username: ");
    String username = scan.nextLine();
    System.out.printf("Welcome to Casey's Classic Coffee, %s!%n", username);
    displayMenu();
    displayOutput(scan);
    System.out.printf("Thank you %s! Have a nice day!", username);
}

// outputs the menu to the screen
public static void displayMenu() {
    MenuItem[] items = MenuItem.values();
    for (int i = 0; i < items.length; i++) {
        System.out.printf("%d %s%n", i + 1, items[i]);
    }
}

public static int getItemNumber(Scanner scan) {
    System.out.println("Please enter the desired item number: ");
    return scan.nextInt();
}

public static int getQuantity(Scanner scan) {
    System.out.println("Please enter the quantity: ");
    return scan.nextInt();
}

public static double computeSubTotal(Scanner scan) {
    int number = getItemNumber(scan);
    int quantity = getQuantity(scan);

    return quantity * MenuItem.values()[number - 1].cost;
}

public static boolean discountCheck(double cost) {
    return (cost >= 10);
}

public static double computeDiscount(double cost) {
    if (discountCheck(cost)) {
        return cost * 0.10;
    }
    return 0;
}

public static double computePriceAfterDiscount(double cost, double discount) {
    return cost - discount;
}

public static double computeTax(double Discounted_cost) {
    return Discounted_cost * 0.07;
}

public static double computeTotal(double Discounted_cost, double tax) {
    return Discounted_cost + tax;
}

public static void displayOutput(Scanner scan) {
    double cost = computeSubTotal(scan);
    double discount = computeDiscount(cost);
    double Discounted_cost = computePriceAfterDiscount(cost, discount);
    double tax = computeTax(Discounted_cost);
    double Total_cost = computeTotal(Discounted_cost, tax);

    System.out.printf("Total before discount and tax: $%.2f%n", cost);

    System.out.printf("Calculated discount: $%.2f%n", discount);
    System.out.printf("Total after special discount: $%.2f%n",
            Discounted_cost);

    System.out.printf("Tax: $%.2f%n", tax);
    System.out.printf("Total cost: $%.2f%n", Total_cost);
}