Author: Jonas Bilinkevicius

How to calculate the age based on the date of birth.

Answer:

Solve 1:

1   { BrthDate:  Date of birth }
2   
3   function TFFuncs.CalcAge(brthdate: TDateTime): Integer;
4   var
5     month, day, year, bmonth, bday, byear: word;
6   begin
7     DecodeDate(BrthDate, byear, bmonth, bday);
8     if bmonth = 0 then
9       result := 0
10    else
11    begin
12      DecodeDate(Date, year, month, day);
13      result := year - byear;
14      if (100 * month + day) < (100 * bmonth + bday) then
15        result := result - 1;
16    end;
17  end;



Solve 2:
18  
19  procedure TForm1.Button1Click(Sender: TObject);
20  var
21    Month, Day, Year, CurrentMonth, CurrentDay, CurrentYear: word;
22    Age: integer;
23  begin
24    DecodeDate(DateTimePicker1.Date, Year, Month, Day);
25    DecodeDate(Date, CurrentYear, CurrentMonth, CurrentDay);
26    if (Year = CurrentYear) and (Month = CurrentMonth) and (Day = CurrentDay) then
27      Age := 0
28    else
29    begin
30      Age := CurrentYear - Year;
31      if (Month > CurrentMonth) then
32        dec(Age)
33      else if Month = CurrentMonth then
34        if (Day > CurrentDay) then
35          dec(Age);
36    end;
37    Label1.Caption := IntToStr(Age);
38  end;