Homework
Due: 13 Feb

Using the bookFiles/ch01 Date and IncDate classes, modify them to
include:

1.
Add to the IncDate class a correct increment method.

Remember the rule for leap years:
A year is a leap year if it is divisible by 4, unless it is divisible
by 100 (in which case it's not a leap year) UNLESS it's also divisible
by 400 (in which case it's a leap year):
 year%4==0 && year%100!=0 || year%400==0 
(1900 was not a leap year, but 2000 is, 2100 will not be).

2.
Add a constructor that takes a String parameter that is in the form
mm/dd/yyyy (no leading zeroes), extracts the month, day and year parts
and uses those to initialize the instance variables of the Date object
being constructed.  Its signature is this:
public Date( String )
This is like the opposite of the toString method.  It could be called
fromString or toDate.
Assume the parameter has no errors.
Hint: How to extract the parts from a string?  You could use the
String class indexOf() and substring() methods to find the slashes and
get the intervening substrings but a better way is to use
a StringTokenizer, which is in java.util:

String s="here:is:a:  bunch:of:words:separated  by:colons!";
StringTokenizer st = new StringTokenizer( s, ":" );  
                     //optional 2nd parameter is delimiter (default is space)
while (st.hasMoreTokens())   //iterate over the tokens
  System.out.println(st.nextToken());   
              //each call of nextToken() gets the next token (word)

3.
Add a copy constructor.  It's on page 122.


Use the TDIncDate241HmkArray.java program as a test driver.  It works
with the Date and IncDate classes of ch01.  To test your modifications
of those classes uncomment the parts of TDIncDate241HmkArray.java that
use the additional methods. Do not otherwise modify the test driver. I
will test your code using my copy of TDIncDatge241HmkArray.  Submit
your Date.java and IncDate.java zipped into one file and attached.