====== IBPP::Date ======
The IBPP::Date class represents a date value. It is not an interface class, with automatic smart pointer management like for instance the [[Database]] class. It is a plain classical C++ class. Use it to interact easily with DATE (SQL) columns in your databases.

===== Definition =====

See the file ibpp.h for an up-to-date definition.

A Date is internally made of a simple integer, representing the numbers of days elapsed since the 31 december 1899 (which means the 1 january 1900 value is 1). Being made only of an integer as its data part, the class Date is a light object which you can use without fear of bulky data structures.

===== Methods =====

==== void Clear() ====

Resets the date to an invalid value (actually -1), effectively clearing the value.

==== void Today() ====

Sets the date to today's date.

==== void SetDate(int year, int month, int day) ====

Sets the date based on the numeric values of the year, month and day. Any invalid values will lead to an invalid date value (-1).

==== SetDate(int dt) ====

Sets the date based on a integer value, as the one internally stored in the date object itself. See the int GetDate() method too.

==== void GetDate(int& year, int& month, int& day) ====

Gets a date in its basic components year, month, day.

==== int GetDate() ====

Returns the internal integer representing the date value.

==== int Year(), int Month(), int Day() ====

Returns the year, month, day value of the Date.

==== void Add(int days) ====

Add days to a date. The new date is the original one, 'days' later. This of course takes care of everything, overlapping months and years, months or different numbers of days, leap years,...

==== void StartOfMonth() ====

Adjust a date to the first day of the same month.

==== void EndOfMonth() ====

Adjust a date to the last day of the same month, taking into consideration months of varying number of days, including leap years support.

===== Constructors =====

==== Date() ====

The default constructructor builds an empty date (invalid value), same as if Clear() was called on an existing date.

==== Date(int dt) ====

Similarly to the SetDate(int) method, this form of the constructor builds a date out of the internal representation of another one.

==== Date(int year, int month, int day) ====

Similarly to the SetDate(int, int, int) method, this form of the constructor builds a date our of its basic components (year, month, day).

==== Date(const Date&) ====

Ordinary copy constructor. To make the Date a good citizen of your code.

===== Operators =====

==== Date& operator=(const Date&) ====

To assign a date from another one.

==== Date& operator=(const Timestamp&) ====

To assign a date from the date portion of a [[Timestamp]] object.

==== bool operator==(const Date&) ====

To compare two Dates for equality.

==== bool operator<(const Date&) ====

To compare if one Date is strictly 'lower' (the date is before) the other.

===== See also =====

These classes are closely related to this one :
  * [[Time]]
  * [[Timestamp]]