约达时间

Question

此代码的问题在于它确实只为某些出生日期计算了活着的天数。我尝试使用不同的出生日期并使用在线计算器进行测试，但似乎并非所有都是正确的。我认为这个问题是因为Leapyears，一个月内不到30天。

public class DaysAlive {

public static void main (String [] args){

    Scanner userInput = new Scanner(System.in);

    int TodayYear, TodayMonth, TodayDay;
    int YearBorn, MonthBorn, DayBorn;
    int DaysAlive;

    System.out.println("Enter today's date");
    System.out.print ("Year: ");
    TodayYear = userInput.nextInt ();
    System.out.print ("Month: ");
    TodayMonth = userInput.nextInt ();
    System.out.print ("Day: ");
    TodayDay = userInput.nextInt ();

    System.out.println("Enter date of birth");
    System.out.print ("Year: ");
    YearBorn = userInput.nextInt ();
    System.out.print ("Month: ");
    MonthBorn = userInput.nextInt ();
    System.out.print ("Day: ");
    DayBorn = userInput.nextInt ();

    //I think this line is the problem 
    DaysAlive = (TodayYear - YearBorn) *365 + (TodayMonth - MonthBorn) *30 +(TodayDay - DayBorn);

    System.out.println("DaysAlive: " + DaysAlive);



      }
}

Answer 1

如何使用日历？它会为你做所有这些...或者joda时间库

在这里查看： Getting the number of days between two dates in java

Answer 2

如果我理解你想要的东西，你应该可以使用这样的东西 -

public static void main(String[] args) {
    Scanner userInput = new Scanner(System.in);

    System.out.println("Enter today's date");
    System.out.print("Year: ");
    int todayYear = userInput.nextInt();
    System.out.print("Month: ");
    int todayMonth = userInput.nextInt();
    System.out.print("Day: ");
    int todayDay = userInput.nextInt();

    // Java has January as month 0. Let's not require that the user know.
    Calendar today = new GregorianCalendar(todayYear, todayMonth - 1,
            todayDay);

    System.out.println("Enter date of birth");
    System.out.print("Year: ");
    int yearBorn = userInput.nextInt();
    System.out.print("Month: ");
    int monthBorn = userInput.nextInt();
    System.out.print("Day: ");
    int dayBorn = userInput.nextInt();
    Calendar born = new GregorianCalendar(yearBorn, monthBorn - 1, dayBorn);

    double diff = today.getTimeInMillis() - born.getTimeInMillis();
    diff = diff / (24 * 60 * 60 * 1000); // hours in a day, minutes in a hour,
                                    // seconds in a minute, millis in a
                                    // second.
    System.out.println(Math.round(diff));
}

带输出

Enter today's date
Year: 2014
Month: 03
Day: 14
Enter date of birth
Year: 2014
Month: 03
Day: 13
1

Answer 3

你是对的，问题是并非所有月份都有30天。一个简单的解决方案是使用if语句并创建另一个名为monthMultiplier的整数变量。正如其他人指出你也可以使用日历

    if(TodayMonth == 9 || TodayMonth == 11 || TodayMonth == 4 || TodayMonth == 6) {
          monthMultiplier = 30;//30 days in these months

    } 

    if(TodayMonth == 2){
       monthMultiplier = 28;//WELL 28.25 accounting for leap years
    }

    else {
         monthMultiplier = 31;
}

    DaysAlive = (TodayYear - YearBorn) *365 + (TodayMonth - MonthBorn) * monthMultiplier +(TodayDay - DayBorn);

Answer 4

约达时间

Joda-Time库可以轻松解决此问题。基本上只有一行代码。 Joda-Time处理时区，闰日和其他问题。

手动编码这样的日期时间工作是冒险的，容易出错，并且鉴于可用的优秀库（Joda-Time和Java 8中的新java.time包），坦率地说是愚蠢的。

示例代码

以下是Joda-Time 2.3中的一些示例代码。

DateTimeZone timeZone = DateTimeZone.forID( "Europe/Paris" );

DateTime start = new DateTime(2008, 4, 26, 0, 0, 0, timeZone);
DateTime stop = new DateTime(2008, 5, 26, 0, 0, 0, timeZone);

int daysBetween = Days.daysBetween( start, stop ).getDays();

转储到控制台...

System.out.println( "start: " + start );
System.out.println( "stop: " + stop );
System.out.println( "daysBetween: " + daysBetween );

执行时......

start: 2008-04-26T00:00:00.000+02:00
stop: 2008-05-26T00:00:00.000+02:00
daysBetween: 30

确定已用天数的Java代码未返回正确答案

4 个答案:

约达时间

示例代码