Keep Calm and Code in Delphi - #3

💡 Linked Lists

Linked Lists are one of the most powerful and flexible data structures, widely used to implement queues, stacks, or even in systems that require dynamic data manipulation.

Why use linked lists?

✅ Efficient Insertion/Removal: Unlike arrays, linked lists allow quick insertions and deletions at any position without requiring the movement of elements.

✅ Dynamic Memory Allocation: Linked lists grow as needed, making them a more efficient option compared to fixed-size arrays.

Implementing a Simple List:

type
  TNode = class
  public
    Data: Integer;
    Next: TNode;
    constructor Create( AData: Integer );
    procedure AddNode( AData: Integer );
    procedure PrintList;
end;

constructor TNode.Create( AData: Integer );
begin
  Data := AData;
  Next := nil;
end;

procedure TNode.AddNode( AData: Integer );
var
  NewNode: TNode;
begin
  NewNode := TNode.Create( AData ); // Creates a new node
  Self.Next := NewNode; // Links the new node to the current one
end;

procedure TNode.PrintList;
var
  Temp: TNode;
begin
  Temp := Self;
   while Temp <> nil do
   begin
     Writeln( Temp.Data );
     Temp := Temp.Next;
   end;
end;        

Example Usage:

var
  Head, Tail: TNode;

begin
  Head := TNode.Create(11); 
  Tail := Head; // Tail starts by pointing to the first node

  Tail.AddNode(18); 
  Tail := Tail.Next; // Update Tail to point to the second node

  Tail.AddNode(24);
  Tail := Tail.Next; // Update Tail to point to the third node

  Head.PrintList;
end.        

🔥Advantages:

🔹 Ease of Manipulation: Allows easy insertion and removal of elements at any position in the list.

🔹 Dynamic Structure: No need to define the size of the list in advance; memory is allocated as required.

🔹 Flexibility: Can be used to implement other structures, such as queues, stacks, and even graphs!

👉 Tip: While Delphi’s TList class is excellent for most use cases, understanding the mechanics of linked lists is invaluable for optimizing resources and gaining deeper insights into dynamic memory management!

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