Java 字符串错误

Question

我正在尝试解决以下问题，但是在输入值后它不会计算。我希望这可以很快得到纠正，并且没有弄错 if-else 语句？谢谢！

编写一个名为 season 的方法，该方法接受两个整数作为参数，分别代表一个月数和一个天数，并返回一个表示该月和日的季节的字符串。假设月份指定为 1 到 12 之间的整数（1 表示一月，2 表示二月，依此类推），并且该月的日期是 1 到 31 之间的数字。 如果日期介于 12/16 和 3/15 之间，则应返回“Winter”。如果日期介于 3/16 和 6/15 之间，则应返回“Spring”。如果日期介于 6/16 和 9/15 之间，则应返回“Summer”。如果日期介于 9/16 和 12/15 之间，则应返回“Fall”。”

import java.util.Scanner;

public class Seasons
{
  public static void main(String[] args)
{
 Scanner keyboard = new Scanner(System.in);
 System.out.println("This program reports the season for a given day and month");
 System.out.print("Please enter the month and day as integers with a space between the month and day:");
 int month = keyboard.nextInt();
 int day = keyboard.nextInt();
 }

public static String season(int month, int day)

{

if ((month == 12 && day >= 16) || (month == 3 || day <= 15) || (month == 1 || month == 2))
return "Winter";

if ((month == 3 && day >= 16) || (month == 6 || day <= 15) || (month == 4 || month == 5))
return "Spring";

if ((month == 6 && day >= 16) || (month == 9 || day <= 15) || (month == 7 || month == 8))
return "Summer";

if ((month == 9 && day >= 16) || (month == 12 || day <= 15) || (month == 10 || month == 11))
return "Fall";

else
  {
     return "impossible!";
  }
}
}

Answer 1

你还没有调用方法season。

添加行：

System.out.println(Seasons.season(month, day));

到main 方法的末尾。这将调用该方法并打印其返回值。

您甚至可以改进您的解决方案： 您是否已经考虑过输入验证？如果用户输入Monday怎么办？还是数字太大？

Answer 2

你没有在任何地方调用 season 方法。因为 season 是一个静态方法，所以你不需要创建一个对象。调用这种格式的方法 classname.staticmethod()

import java.util.Scanner;

public class Seasons
{
  public static void main(String[] args)
{
 Scanner keyboard = new Scanner(System.in);
 System.out.println("This program reports the season for a given day and month");
 System.out.print("Please enter the month and day as integers with a space between the month and day:");
 int month = keyboard.nextInt();
 int day = keyboard.nextInt();
String result=Seasons.season(month,day)
System.out.println(result);
 }

public static String season(int month, int day)

{

if ((month == 12 && day >= 16) || (month == 3 || day <= 15) || (month == 1 || month == 2))
return "Winter";

if ((month == 3 && day >= 16) || (month == 6 || day <= 15) || (month == 4 || month == 5))
return "Spring";

if ((month == 6 && day >= 16) || (month == 9 || day <= 15) || (month == 7 || month == 8))
return "Summer";

if ((month == 9 && day >= 16) || (month == 12 || day <= 15) || (month == 10 || month == 11))
return "Fall";

else
  {
     return "impossible!";
  }
}
}

Answer 3

import java.util.Calendar;
import java.util.GregorianCalendar;

...

    public static String season(int month, int day){
        Calendar today = new GregorianCalendar();
        int year = today.get(Calendar.YEAR);
        if(inBetween(year, 3, 16, year, 6, 15, year, month, day))
            return "Spring";
        else if(inBetween(year, 6, 16, year, 9, 15, year, month, day))
            return "Summer";
        else if(inBetween(year, 9, 16, year, 12, 15, year, month, day))
            return "Fall";
        else if(inBetween(year, 12, 16, year,  12, 31, year,   month, day)||
                inBetween(year+1,1,  1, year+1, 3, 15, year+1, month, day))
            return "Winter";
        return "impossible";
    }
    public static boolean inBetween(int startY, int startM, int startD,
                                    int endY,   int endM,   int endD,
                                    int year,   int month,  int day){
            Calendar startDay = new GregorianCalendar();
            startDay.clear();
            startDay.set(startY, startM-1, startD);
            Calendar endDay = new GregorianCalendar();
            endDay.clear();
            endDay.set(endY, endM-1, endD);
            Calendar checkDay = new GregorianCalendar();
            checkDay.clear();
            checkDay.set(year, month-1, day);
            //startDay <= checkDay && checkDay <= endDay
            return startDay.compareTo(checkDay)<=0 && checkDay.compareTo(endDay)<=0;
    }