program10_5.java

《A first book of java》by Gary J.Bronson 北大出版社

import java.text.*;  // needed for formatting
public class Date
{
  // class variable declaration section
  private int month;
  private int day;
  private int year;
  
  // class method definition section
 
  public Date(int mm, int dd, int yyyy) // constructor
  {
    this.month = mm;
    this.day = dd;
    this.year = yyyy;
  }
  public void showdate()
  {
    DecimalFormat df = new DecimalFormat("00");
    
    System.out.print(df.format(this.month)
                       + '/' + df.format(this.day) + '/' 
                       + df.format(this.year % 100)); 
  }
  public static void main(String[] args)
  {
    Date a = new Date(04,01,1999); // create two Date objects
    Date b = new Date(12,18,2001);
    System.out.print("\nThe date stored in a is originally ");
    a.showdate();  // display the original date
    a = b;         // assign b's value to a
    System.out.print("\nAfter assignment the date stored in a is ");
    a.showdate();  // display a's values
    System.out.println();
  }
}