public class Date3                          //類的封裝
{ 
    private  int year,month,day;            //成員變量,私有的
    public Date3(int y,int m,int d)
    {
        year = y;
        month = (((m>=1) & (m<=12)) ? m : 1);
        day = (((d>=1) & (d<=31)) ? d : 1);
    } 
    public int getyear()                    //成員方法,公有的
    {
        return year;
    }
    public boolean isleapyear()
    {
        return (year%400==0) | (year%100!=0) & (year%4==0);
    }
    public void print() 
    {
        System.out.println("date is "+year+'-'+month+'-'+day);
    }
}
class Date3_ex                              //其他類
{
    public static void main(String args[]) 
    {
        Date3 a = new Date3(2002,6,28) ;
        a.print();
        System.out.println(a.getyear()+" is a leap year,"+a.isleapyear());
    }
}