Question

How to create a list of random dates in Pascal

Answer 1

program RandomDates;

{$mode objfpc}{$H+}

uses
  SysUtils, DateUtils, Math;

// Generate a random date between two years using TDateTime
function RandomDate(startYear, endYear: Integer): TDateTime;
var
  startDate, endDate: TDateTime;
  rangeDays: Integer;
  offset: Integer;
begin
  // Convert start and end years to timestamps
  startDate := EncodeDate(startYear, 1, 1);
  endDate   := EncodeDate(endYear, 12, 31);

  // Uniform distribution over the timestamp range
  rangeDays := Trunc(endDate - startDate);
  offset := Random(rangeDays + 1);

  Result := startDate + offset;
end;

var
  dates: array of TDateTime;
  d: TDateTime;
  i: Integer;
  y, m, day: Word;

begin
  Randomize; // Seed RNG

  SetLength(dates, 10);

  for i := 0 to High(dates) do
  begin
    dates[i] := RandomDate(1990, 2030);
  end;

  for d in dates do
  begin
    DecodeDate(d, y, m, day);
    WriteLn(y, '-', m, '-', day);
  end;
end.



(*
run:

1996-4-6
2023-9-21
2011-9-15
2005-4-18
2001-4-10
2002-3-2
2022-9-26
2011-10-24
2010-7-3
2029-3-25

*)

 

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