如何在不重复的情况下随机提问？

Question

**So I have to make a random question for my logic quiz and I have a written code here. I do not know what is the syntax for java because I just started learning it and I started with kotlin so it is a bit unfamiliar to me. Here is the code: **

       Random r;
String [] quest = {"Which alphabet will be 14th to the left of 8th alphabet from the right in the following series of letters?" +
        "A O B P C Q D R E S F T G U H V I W J X K Y L Z M N.", "Hritik is taller than Salman who is shorter than Sanjay. Akshay is taller than " +
        "Shahrukh but shorter than Salman. Sanjay is shorter than Hritik. Who is the tallest?" , "Lali and Anju are a married couple. Tunu and Munu " +
        "are brothers. Tunu is the brother of Lali. How is Munu related to Anju?", "How many sets of two letters have as many letters " +
        "between them as in the English alphabetical order in the word ‘WRISTWATCH’."};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_easy);

    Button question = findViewById(R.id.btnQuestion);
    final TextView ask = findViewById(R.id.txtAsk);

    r = new Random();


    question.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            ask.setText(quest[r.nextInt(quest.length)]);



        }
    });
}

Answer 1

Do it as follows:

Random r = new Random();
String [] quest = {"Which alphabet will be 14th to the left of 8th alphabet from the right in the following series of letters?" +
        "A O B P C Q D R E S F T G U H V I W J X K Y L Z M N.", "Hritik is taller than Salman who is shorter than Sanjay. Akshay is taller than " +
        "Shahrukh but shorter than Salman. Sanjay is shorter than Hritik. Who is the tallest?" , "Lali and Anju are a married couple. Tunu and Munu " +
        "are brothers. Tunu is the brother of Lali. How is Munu related to Anju?", "How many sets of two letters have as many letters " +
        "between them as in the English alphabetical order in the word ‘WRISTWATCH’."};

boolean [] usedIndices = new boolean[quest.length];        

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_easy);

    Button question = findViewById(R.id.btnQuestion);
    final TextView ask = findViewById(R.id.txtAsk);

    question.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            int indextoBeUsed;
            do {
                indextoBeUsed = r.nextInt(quest.length);             
            } while (usedIndices[indextoBeUsed]);
            usedIndices[indextoBeUsed] = true;
            ask.setText(quest[indextoBeUsed]);
        }
    });
}

The solution is quite straight forward. Feel free to comment in case of any doubt.