命名约定

Question

所以这就是我到目前为止所有类getDayInMonth必须保持不变，我希望它计算它匹配的次数。你好吗？

public class Real {

    public static void main(String[] args) {

        int realmonth = 5;
        int realday= 11;
        int count = 0;

        for(int iteration = 1; iteration <=100; iteration ++) {
            Random Month = new Random();
            int month = Month.nextInt(12) + 1;
            if(realmonth == month) count++;
            System.out.println("The correct birthday was found " + count + " times during the 100 iterations.");
        }

    public static int getDayInMonth(int month) {

        final int JANUARY = 1;  final int JULY = 7;
        final int FEBRUARY = 2; final int AUGUST = 8;
        final int MARCH = 3;    final int SEPTEMBER = 9;
        final int APRIL = 4;    final int OCTOBER = 10;
        final int MAY = 5;      final int NOVEMBER = 11;
        final int JUNE = 6;     final int DECEMBER = 12;

        Random dayGenerator = new Random();
        switch (month) {

        case JANUARY: case MARCH: case MAY: case JULY:
        case AUGUST: case OCTOBER: case DECEMBER:
            return dayGenerator.nextInt(31) + 1;

        case APRIL: case JUNE: case SEPTEMBER: case NOVEMBER:
            return dayGenerator.nextInt(30) + 1;

        case FEBRUARY:
            return dayGenerator.nextInt(28) + 1;

        default:
            return -1;
        }
    }
}

Answer 1

    for (int iteration = 1; iteration <= 10000; iteration++) {
        Random Month = new Random();
        int month = Month.nextInt(12) + 1;
        // Added call to getDayInMonth
        if (realmonth == month && getDayInMonth(month) == realday) {
            count++;
        }
    }
    // Moved this outside for loop
    System.out.println("The correct birthday was found " + count + " times during the 100 iterations.");

为了简化您的代码，您可以随机选择一年中的某一天，即365，因为您似乎没有将闰年考虑在内

    Random r = new Random();
    int realDate = r.nextInt(365) + 1; 
    // Or assign one yourself with 
    // LocalDate.of(2013, 4, 31).getDayOfYear();

    int count = 0;
    for (int iteration = 1; iteration <= 10000; iteration++) {
        int randDate = r.nextInt(365) + 1;
        if (randDate == realDate) {
            count++;
        }
    }

Answer 2

你很亲密。问题是如何调用getDayInMonth方法。这是一个方法，而不是您在问题中错误陈述的类。

此方法为static，表示它独立于此类的实例。换句话说，不是面向对象的。所以我们用类名称来称呼它。

int dayOfMonth = Real.getDayOfMonth( month ) ;

扩展您的if以测试month和dayOfMonth。

boolean monthMatch = ( month == realMonth ) ;
boolean dayOfMonthMatch = ( dayOfMonth == realDay ) ;
if ( monthMatch && dayOfMonthMatch ) { count++ ; }

请注意，按照惯例，Java程序员通常在if语句中包含大括号，即使对于单行也是如此。

命名约定

在Java中，实例以小写的第一个字母命名。因此，Random Month应为Random month。但是你已经有了这样一个变量名，所以把它变成Random monthRandom。

另外，我会将其替换为：

int month = ThreadLocalRandom.current().nextInt( 1 , 13 ) ;

我们在那里使用13因为绑定是独占，所以12 + 1 = 13.请参阅class documentation。

java.time

顺便说一下，在实际工作而不是学校作业中，我们会使用java.time类来解决这个问题，例如Month和MonthDay。

我的主要方法必须重复这100次：随机生成数字1到12，使用getDayInMonth随机生成天数？

2 个答案:

命名约定

java.time