C# 每次使用时的唯一编号，但不使用。你必须在某种收集中自己追踪它们。 static void Main(string[] args) { List<string> questions = new List<st

每次使用时的唯一编号，但不使用。你必须在某种收集中自己追踪它们。

    static void Main(string[] args)
    {
        List<string> questions = new List<string>();
        for (int i = 0; i < 10; i++)
            questions.Add("Question " + i);

        Random r = new Random();
        for (int i = 0; i < 3; i++)
        {
            int nextQuestion = r.Next(0, questions.Count);
            Console.WriteLine(questions[nextQuestion]);
            questions.RemoveAt(nextQuestion);
        }
    }

class Questions
{
    const int NUMBER_OF_QUESTIONS = 10;
    readonly List<string> questionsList;
    private bool[] avoidQuestions; // this is the "do-not-ask-question" list
    public Questions()
    {
        avoidQuestions = new bool[NUMBER_OF_QUESTIONS];

        questionsList = new List<string>
                            {
                                "question1",
                                "question2",
                                "question3",
                                "question4",
                                "question5",
                                "question6",
                                "question7",
                                "question8",
                                "question9"
                            };            
    }

    public string GetQuestion()
    {
        Random rnd = new Random();
        int randomVal;

        // get a new question if this question is on the "do not ask question" list
        do
        {
            randomVal =  rnd.Next(0, NUMBER_OF_QUESTIONS -1);
        } while (avoidQuestions[randomVal]);

        // do not allow this question to be selected again
        avoidQuestions[randomVal] = true;

        // do not allow question before this one to be selected
        if (randomVal != 0)
        {
            avoidQuestions[randomVal - 1] = true;
        }

        // do not allow question after this one to be selected
        if (randomVal != NUMBER_OF_QUESTIONS - 1)
        {
            avoidQuestions[randomVal + 1] = true;
        }

        return questionsList[randomVal];
    }
}