Some countries have integer numbers printed on the transport tickets, for example, in ex-USSR. The ticket is "happy" when the sum of the first half of digits equals to the second one. Then you should eat it and make a wish.

Example:

123456 and 111222 are not happy tickets
123123 …

Here is the code explaining some methods to pack bit accessing logic in your program.

program project1;

type
  TRec1 = packed record // Doesn't pack at all
    b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16: boolean;
  end;

  TRec2 = bitpacked record // Free Pascal specific …

In theory, hash map structure should be very fast on retrieving by key operations, close to O(1) like for an array. A sorted map (keys are sorted) should be O(log₂ N) instead. The following test checks the difference.

Common scenario

We will use one tester class per …

Free Pascal (like Delphi) provide some useful functions to watch heap memory state in your application.

function GetHeapStatus: THeapStatus;

THeapStatus is documented here

Example of using this function is below

program ProgWatchMem;

uses
  Math, FGL;

type
  TLongIntArr = array of LongInt; // LongInt is a 4-byte signed integer
  PLongIntArr = ^TLongIntArr;
  TMySortedMap = specialize …

In the previous article "Crack C# namespaces in 30 seconds" I demonstrated how to make error having no idea about it. So you will have a lovely time in debugging. But in C# you're condemned to use using directive or your code will be unreadable with all these horrible specifiers …

Here is an example how to get N-2 calling procedure information.

Warning: code seeking debugging info is slow so be aware to use it in loops.

Make sure to compile with following options:

• -gl (not requierd but show file and line numbers info)
• -gs (show proc name after address)

var …

Let's perform a simple benchmark testing the random and sequential access to arrays and lists. I would like to compare:

• static array with predefined size (allocated on stack)
• TList container class (allocated on heap)
• dynamic array (allocated on heap)
• generic Delphi TList or Free Pascal TFPGList (allocated on heap)

I …

The code below show how to implement very simple but cross-platform "old school" mutex (mutually exclusive semaphore)

interface

type
  TMutex = class
  private
    FFileHandle: integer;
  public
    constructor Create(const AName: string; const WaitForMSec: integer = 10000);
    destructor Destroy; override;
  end;

implementation

uses
  Classes, SysUtils, DateUtils,
  {$IFDEF MSWINDOWS}
  Windows
  {$ENDIF};

function GetTempDir: string …