[Overview][Constants][Types][Classes][Procedures and functions][Index] | Reference for unit 'contnrs' (#fcl)

# TOrderedList

[Properties (by Name)] [Methods (by Name)] [Events (by Name)]

Base class for queues and stacks.

## Declaration

Source position: contnrs.pp line 129

`type TOrderedList = class(TObject)`
`protected`
`procedure PushItem(); virtual; abstract;`
`function PopItem; virtual;`
`function PeekItem; virtual;`
`property List: TList; [r]`
`public`
`constructor Create;` |  | Create a new ordered list
`destructor Destroy; override;` |  | Free an ordered list
`function Count;` |  | Number of elements on the list.
`function AtLeast();` |  | Check whether the list contains a certain number of elements.
`function Push();` |  | Push another element on the list.
`function Pop;` |  | Remove an element from the list.
`function Peek;` |  | Return the next element to be popped from the list.
`end;`

## Inheritance

`TOrderedList` |  | Base class for queues and stacks.
`TObject`

## Description

TOrderedList provides the base class for TQueue and TStack. It provides an interface for pushing and popping elements on or off the list, and manages the internal list of pointers.

Note that TOrderedList does not manage objects on the stack, i.e. objects are not freed when the ordered list is destroyed.

## See also

TQueue |  | Pointer queue
TStack |  | Pointer Stack

The latest version of this document can be found at lazarus-ccr.sourceforge.net .