每次在测验中加载应用程序时随机化问题

Question

每当有人运行我的应用程序时，我都会尝试随机分配一组问题。 现在我有

-(void)Category1{

    int QuestionSelected = rand() % 100;

    switch (QuestionSelected) {
        case 0:
            QuestionText.text = [NSString stringWithFormat:@"Here is where my first question is"];
            [Answer1 setTitle:@"First multiple choice" forState:UIControlStateNormal];
            [Answer2 setTitle:@"Second multiple choice" forState:UIControlStateNormal];
            [Answer3 setTitle:@"Third multiple choice" forState:UIControlStateNormal];
            [Answer4 setTitle:@"Fourth multiple choice" forState:UIControlStateNormal];
            Answer1Correct = YES;
            CorrectAnswerDisplay.text = [NSString stringWithFormat:@"Right Answer"];
            break;
        case 1:
            QuestionText.text = [NSString stringWithFormat:@"Here is where my second question is"];
            [Answer1 setTitle:@"First multiple choice" forState:UIControlStateNormal];
            [Answer2 setTitle:@"Second multiple choice" forState:UIControlStateNormal];
            [Answer3 setTitle:@"Third multiple choice" forState:UIControlStateNormal];
            [Answer4 setTitle:@"Fourth multiple choice" forState:UIControlStateNormal];
            Answer1Correct = YES;
            CorrectAnswerDisplay.text = [NSString stringWithFormat:@"Right Answer"];
            break;

这一切都很好，很花哨，但只随机化了一次。 因此，它随机化了我所有的100个问题，但是如果我关闭我的应用程序并从头开始再次运行它，它将以与之前相同的方式随机化，因此它的运行与之前对相同问题的完全相同。 有比我的rand（）行更好的东西吗？

Answer 1

rand需要发出呼吁srand种子。 更好的是，将您对rand的使用替换为arc4random或arc4random_uniform 。 它不需要种子，可以提供更好的结果。

Answer 2

替换此行：-

    int QuestionSelected = rand() % 100;

修改如下：

   int QuestionSelected=(int)
   arc4random_uniform(100)