我如何跟蹤正確答案？

Question

public static void main(String[] args) {
    Scanner Keyboard = new Scanner(System.in);
    System.out.println("Enter your name: ");
    String firstname =Keyboard.nextLine();
    System.out.println("Welcome "+ firstname+  "!"+ " Please answer the following questions:");
    int x =  (int)(20 * Math.random()) + 1;
    int y =  (int)(20 * Math.random()) + 1;

    int sum = (x+y);
    System.out.println(x + " + " + y + " = ");
    String sInput = Keyboard.nextLine();
    int answer1 = Integer.parseInt(sInput);
    if (answer1 ==sum){
        System.out.println("Correct!");
    }else{
    System.out.println("Wrong!");
    }
    System.out.println("The correct answer is " +sum);

我不知道如何跟蹤正確答案。 我需要一些東西來跟蹤打印正確的時間。 我不知道該怎么做。 我知道我只需要記錄正確並除以四。 四，因為這就是我的測驗中有多少問題。

Answer 1

如果您只需要跟蹤提供了多少正確答案，只需添加一個從 0 開始的 int 變量作為值並遞增它。 如果您想跟蹤正確的問題和答案，請創建一個空的 ArrayList 並在每次提供正確答案時添加一個字符串。

這是第二個選項的示例：

    ArrayList<String> correctAnswers = new ArrayList<String>();
    Scanner keyboard = new Scanner(System.in);
    System.out.println("Enter your name: ");
    String firstname =keyboard.nextLine();
    System.out.println("Welcome "+ firstname+  "!"+ " Please answer the following questions:");
    for (int i=0;i<10;i++) {
        int x =  (int)(20 * Math.random()) + 1;
        int y =  (int)(20 * Math.random()) + 1;

        int sum = (x+y);
        System.out.println(x + " + " + y + " = ");
        String sInput = keyboard.nextLine();
        int answer1 = Integer.parseInt(sInput);
        if (answer1 ==sum){
            System.out.println("Correct!");
            correctAnswers.add(x + " + " + y + " = " + sum);
        }
        else{
            System.out.println("Wrong!");
            System.out.println("The correct answer is " +sum);     
        }
    }
    System.out.println("Correct answers:");
    for (String correctAnswer : correctAnswers) {
        System.out.println(correctAnswer);
    }

它提出 10 個問題，跟蹤正確答案並在第 10 個問題之后輸出它們。

第一個選項的示例：

    int correctAnswers=0;
    Scanner keyboard = new Scanner(System.in);
    System.out.println("Enter your name: ");
    String firstname =keyboard.nextLine();
    System.out.println("Welcome "+ firstname+  "!"+ " Please answer the following questions:");
    int totalAnswers=4;
    for (int i=0;i<totalAnswers;i++) {
        int x =  (int)(20 * Math.random()) + 1;
        int y =  (int)(20 * Math.random()) + 1;

        int sum = (x+y);
        System.out.println(x + " + " + y + " = ");
        String sInput = keyboard.nextLine();
        int answer1 = Integer.parseInt(sInput);
        if (answer1 ==sum){
            System.out.println("Correct!");
            correctAnswers++;
        }
        else{
            System.out.println("Wrong!");
            System.out.println("The correct answer is " +sum);     
        }
    }
    System.out.println("Correct answers: "+ correctAnswers + "("+correctAnswers*100/totalAnswers+"%)");