datetest.java

java程序设计 清华出版社 孙燮华老师编写的程序源代码

//DateTest.java
public class DateTest{
  private int day, month, year;
  
  DateTest(int i, int j, int k){//构造方法
    day=i; month=j; year=k;
  }
  DateTest(){                   //构造方法
    day=1; month=7; year=2007;
  }
  DateTest(DateTest d){         //构造方法
    day=d.day; month=d.month; year=d.year;
  }
  public void printDate(){
    System.out.println(day + "/" + month + "/" + year);
  }
  public DateTest tomorrow(){
    DateTest d = new DateTest(this);
    d.day++;
    if(d.day>d.daysInMonth()) {
      d.day = 1; d.month++;
      if(d.month>12){
        d.month = 1; d.year++;
      }
    }
    return d;
  }

  public int daysInMonth() {
    switch(month){
      case 1: case 3: case 5: case 7: //大月
      case 8: case 10:case 12:        //大月
        return 31;  
      case 4: case 6: case 9: case 11://小月
        return 30;  
      default:
        if((year%100 !=0 && year%4==0)||(year%400==0)){//闰年
          return 29;   //闰年，2月
        }
        else return 28;//非闰年，2月  
    }
  }

  public static void main(String args[]){
    DateTest d1=new DateTest();
    System.out.print("The current date is(dd/mm/yy) ");
    d1.printDate();
    System.out.print("Its tomorrow is ");
    d1.tomorrow().printDate();
    
    DateTest d2 = new DateTest(28, 2, 2000);
    System.out.print("The current date is ");
    d2.printDate();
    System.out.print("Its tomorrow is ");
    d2.tomorrow().printDate();
  }
}