類主方法中'if'循環外的變量范圍-不可用的問題

Question

我想存儲弓箭手和野蠻人的價值。 但是，在if語句之外，我無法訪問numberOfArchersToBeTrained和numberOfBarbariansToBeTrained變量。 我在這里做錯了什么？

由於變量numberOfArchersToBeTrained在此處不可用，因此最后一個System.out.println不起作用

public class ConsoleInteraction {

    /**
     * @param args
     */
    public static void main(String[] args) {

        // Create a scanner so we can read the command-line input
        Scanner scanner = new Scanner(System.in);
        // Prompt for training or viewing camp
        System.out.print("What do you want to do: \n 1.Train Troops \n 2. View Troop Camp \n ");
        //Get the preference as an integer
        int preference = scanner.nextInt();

        int numberOfArchersToBeTrained;
        int numberOfBarbariansToBeTrained;

        //Show options based on preference
        if(preference == 1)
        {
            System.out.println("Whom do you want to train?\n 1.Archer \n 2.Barbarian \n 3.Mix \n Enter You preference:");
            int trooppreference = scanner.nextInt();
            if (trooppreference == 1)
            {
                System.out.println("How many Archers you want to train ? : ");
                numberOfArchersToBeTrained = scanner.nextInt();
            }
            else if (trooppreference == 2)
            {
                System.out.println("How many Barbarians you want to train ? : ");
                numberOfBarbariansToBeTrained = scanner.nextInt();
            }
            else if (trooppreference == 3)
            {
                System.out.println("How many Archers you want to train ? :");
                numberOfArchersToBeTrained = scanner.nextInt();
                System.out.println("How many Barbarians you want to train :");    
                numberOfBarbariansToBeTrained = scanner.nextInt();
            }
            else 
            {
                System.out.println("You have to select option 1, 2 or 3");
            }
        }
        else if (preference == 2)
        {
            System.out.println("Showing Camp to You");
        }
        else 
        {
            System.out.println("You can enter only option 1 or 2");
        }    

        System.out.println("Archers:"+ numberOfArchersToBeTrained);

        scanner.close();
    }
}

Answer 1

在開始時初始化numberOfArchersToBeTrained ，您的代碼正在運行；

 int numberOfArchersToBeTrained = 0;

Answer 2

如果偏好是2或3，則沒有初始化numberOfArchersToBeTrained，則需要給此變量值