// Decode procedures
procedure DecodeDate(var Date: TDateTime; var Year, Month, Day: word);
procedure DecodeTime(var Time: TDateTime; var Hour, Minute, Second : word);
procedure DecodeDateTime(var AValue: TDateTime; var AYear, AMonth, ADay, AHour, AMinute, ASecond : word);

// Encode functions
function EncodeDate(Year, Month, Day : word) : TDateTime;
function EncodeTime(Hour, Min, Sec : word) : TDateTime;
function EncodeDateTime(AYear, AMonth, ADay, AHour, AMinute, ASecond : word) : TDateTime;

// Increment/decrement functions.
function IncYear(var AValue: TDateTime; ANumberOfYears: integer ): TDateTime;
function IncWeek(var AValue: TDateTime; ANumberOfWeeks: integer): TDateTime;
function IncDay(var AValue: TDateTime; ANumberOfDays: integer): TDateTime;
function IncHour(var AValue: TDateTime; ANumberOfHours: longint): TDateTime;
function IncMinute(var AValue: TDateTime; ANumberOfMinutes: longint): TDateTime;
function IncSecond(var AValue: TDateTime; ANumberOfSeconds: longint): TDateTime;

// Period functions
function YearsBetween(var ANow, AThen: TDateTime): Integer;
function MonthsBetween(var ANow, AThen: TDateTime): Integer;
function WeeksBetween(var ANow, AThen: TDateTime): Integer;
function DaysBetween(var ANow, AThen: TDateTime): Integer;
function HoursBetween(var ANow, AThen: TDateTime): longint;
function MinutesBetween(var ANow, AThen: TDateTime): longint;
function SecondsBetween(var ANow, AThen: TDateTime): longint;

function IsLeapYear(Year: Word): boolean;
function DayOfWeek(var DateTime: TDateTime): integer;

program DateTimeExample;
uses libDateUtils;

//==============================================================================
var
  // Decalre your date time field
  myDateTime1 : TDateTime;
  myDateTime2 : TDateTime;

  // Helper variables for the example
  i : word;
  diff : longint;
  Year, Month, Day, Hour, Minues, Sec : word;

  tmpString : string[64];

//==============================================================================
begin
  // Encode some date time
  myDateTime1 := EncodeDate(2012, 02, 27); // 40966.00000000
  myDateTime2 := EncodeDateTime(2012, 01, 01, 00, 34, 00); // 40909.02361111

//==============================================================================
  // Decode the date time
  DecodeDateTime(myDateTime1, Year, Month, Day, Hour, Minues, Sec); // 2012-02-27 00:00:00
  DecodeDateTime(myDateTime2, Year, Month, Day, Hour, Minues, Sec); // 2012-01-01 00:34:00

//==============================================================================
  // Increment/decrement functions
  myDateTime1 := IncMinute(myDateTime1, 30);
  myDateTime2 := IncMinute(myDateTime2, -30);
  myDateTime1 := IncSecond(myDateTime1, 1635);
  myDateTime2 := IncYear(myDateTime2, 2);

  // Decode the date time
  // Just to see what the previous inc and dec functions did
  DecodeDateTime(myDateTime1, Year, Month, Day, Hour, Minues, Sec); // 2012-02-27 00:57:15
  DecodeDateTime(myDateTime2, Year, Month, Day, Hour, Minues, Sec); // 2014-01-01 00:04:00

//==============================================================================
  // Period functions
  // You can swop around the myDateTime1 and myDateTime2 to get negative answers
  diff := YearsBetween(myDateTime2, myDateTime1); // 1
  diff := MonthsBetween(myDateTime2, myDateTime1); // 22
  diff := DaysBetween(myDateTime2, myDateTime1); // 673
  diff := HoursBetween(myDateTime2, myDateTime1); // 16175
  diff := MinutesBetween(myDateTime2, myDateTime1); // 970506
  diff := SecondsBetween(myDateTime2, myDateTime1); // 58230404

//==============================================================================
  // Leap Year test (2012 is a leap year)
  myDateTime1 := EncodeDateTime(2012, 02, 27, 00, 00, 00);
  for i := 0 to 4 do
  begin
    myDateTime1 := IncDay(myDateTime1, 1);

    // We decode it only to see the actual output
    // Add the Year, Month, Day, Hour, Minues, Sec valiables to the debugger and
    // step trought this
    DecodeDateTime(myDateTime1, Year, Month, Day, Hour, Minues, Sec);

    // This will give you
    // 2012-02-28
    // 2012-02-29 <== leap year
    // 2012-03-01
    // 2012-03-02
    // 2012-03-03
  end;

//==============================================================================
  // Leap Year test (2011 is NOT a leap year)
  myDateTime1 := EncodeDateTime(2011, 02, 27, 00, 00, 00);
  for i := 0 to 5 do
  begin
    myDateTime1 := IncDay(myDateTime1, 1);

    // We decode it only to see the actual output
    DecodeDateTime(myDateTime1, Year, Month, Day, Hour, Minues, Sec);

    // This will give you
    // 2011-02-28
    // 2011-03-01 <== NOT leap year
    // 2011-03-02
    // 2011-03-03
    // 2011-03-04
  end;

//==============================================================================
  // Print functions
  tmpString := FormatDateTime(myDateTime2);

  // tmpString will now be 2014-01-01 00:04:00 then can be sent to UART or
  // Displayed on the LCD
end.