Einfach verkettete Listen

[TBx]

ja, so würde ich auch löschen.
Nur noch überprüfen, ob es denn überhaupt einen zu löschenden Node gibt

Delphi-Quellcode:

program SingleLinkedList;

{$APPTYPE CONSOLE}

type
  PNode = ^TNode;
  TNode = record
    data: Integer;
    next: PNode;
  end;

var
  FirstNode: PNode;  // Pseudoknoten
  LastNode: PNode;  // Pseudoknoten
  CurrentNode: PNode;

procedure Init;
begin
  // new(FirstNode);  --> überflüssig, Memoryleak
  FirstNode := nil;
  //new(LastNode);  --> überflüssig, Memoryleak
  LastNode := nil;
end;

procedure Add(data: Integer);
begin
  new(CurrentNode);
  CurrentNode.data := data;
//  new(CurrentNode.next);  --> überflüssig, Memoryleak
  CurrentNode.next := nil;
  if LastNode = nil then
  begin
    FirstNode := CurrentNode;
    LastNode := CurrentNode;
  end
  else
  begin
    LastNode.next := CurrentNode;
    LastNode := CurrentNode;
  end;
end;

procedure InsertNodeAfter(Node: PNode; data: Integer);
var
  NewNode: PNode;
begin
  new(NewNode);
  NewNode.data := data;
  NewNode.next := Node.next;
  Node.next := NewNode;
end;

procedure DeleteNextNode(Node: PNode);
var
  TempNode: PNode;
begin
  if (Node.next <> nil) then
  begin
    TempNode := Node.next;
    Node.next := TempNode.next;
    Dispose (TempNode);
  end;
end;

procedure ClearList;
var
  TempNode: PNode;
begin
  CurrentNode := FirstNode;
  while (CurrentNode <> nil) do
  begin
    TempNode := CurrentNode.Next;
    Dispose (CurrentNode);
    CurrentNode := TempNode;
  end;
  Init;
end;

procedure WalkTheList;
begin
  Writeln;
  CurrentNode := FirstNode;
  while CurrentNode <> nil do
  begin
    Writeln(CurrentNode.data);
    CurrentNode := CurrentNode.next;
  end;
end;

var
  i: Integer;
  TempNode: PNode = nil;

begin
  Init;
  for i := 0 to 5 do
  begin
    Add(i);
    if i mod 3 = 0 then
      TempNode := CurrentNode;
  end;
  WalkTheList;

  InsertNodeAfter(TempNode, 9);
  WalkTheList;

  Init;
  for i := 0 to 5 do
  begin
    Add(i);
    if i mod 3 = 0 then
      TempNode := CurrentNode;
  end;
  WalkTheList;

  DeleteNextNode(TempNode);
  WalkTheList;

  Readln;
end.