Question

How to convert days into human-readable years, months and days in Pascal

Answer 1

program DaysToYMD;

type
  TYMD = record
    Years  : Integer;
    Months : Integer;
    Days   : Integer;
  end;

function SplitDays(TotalDays : Integer) : TYMD;
begin
  SplitDays.Years  := TotalDays div 365;
  TotalDays        := TotalDays mod 365;

  SplitDays.Months := TotalDays div 30;
  TotalDays        := TotalDays mod 30;

  SplitDays.Days   := TotalDays;
end;

var
  R : TYMD;

begin
  R := SplitDays(452);

  WriteLn(R.Years, ' years, ', R.Months, ' months, ', R.Days, ' days');
end.




(*
run:

1 years, 2 months, 27 days

*)

 

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Answer 2

program DaysToCalendar;

// Calendar‑accurate (real month lengths)

type
  TYMD = record
    Years  : Integer;
    Months : Integer;
    Days   : Integer;
  end;

const
  MonthLen : array[1..12] of Integer =
    (31,28,31,30,31,30,31,31,30,31,30,31);

function IsLeap(Y : Integer) : Boolean;
begin
  IsLeap := (Y mod 4 = 0) and ((Y mod 100 <> 0) or (Y mod 400 = 0));
end;

function SplitDaysCalendar(TotalDays : LongInt) : TYMD;
var
  Y, M, ML : Integer;
begin
  Y := 1970;
  M := 1;

  { subtract whole years }
  while True do
  begin
    if IsLeap(Y) then ML := 366 else ML := 365;
    if TotalDays < ML then Break;
    Dec(TotalDays, ML);
    Inc(Y);
  end;

  { subtract whole months }
  while True do
  begin
    ML := MonthLen[M];
    if (M = 2) and IsLeap(Y) then Inc(ML); { February in leap year }

    if TotalDays < ML then Break;
    Dec(TotalDays, ML);
    Inc(M);
    if M > 12 then
    begin
      M := 1;
      Inc(Y);
    end;
  end;

  SplitDaysCalendar.Years  := Y - 1970;
  SplitDaysCalendar.Months := M - 1;
  SplitDaysCalendar.Days   := TotalDays;
end;

var
  R : TYMD;

begin
  R := SplitDaysCalendar(452);
  
  WriteLn(R.Years, ' years, ', R.Months, ' months, ', R.Days, ' days');
end.




(*
run:

1 years, 2 months, 28 days

*)

 

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