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// Generic types for NewPascal.org and FPC!
// Original version by keeper89.blogspot.com, 2011
// FPC version by Maciej Izak (hnb), 2014
program TStackProject;
{$MODE DELPHI}
{$APPTYPE CONSOLE}
uses
SysUtils,
Generics.Collections;
type
// We will cook pancakes, put them on a plate and take the last
TPancakeType = (ptMeat, ptCherry, ptCurds);
TPancake = record
strict private
const
PANCAKE_TYPE_NAMES: array [TPancakeType] of string =
('meat', 'cherry', 'curds');
public
var
PancakeType: TPancakeType;
class function Create(PancakeType: TPancakeType): TPancake; static;
function ToString: string;
end;
class function TPancake.Create(PancakeType: TPancakeType): TPancake;
begin
Result.PancakeType := PancakeType;
end;
function TPancake.ToString: string;
begin
Result := Format('Pancake with %s', [PANCAKE_TYPE_NAMES[PancakeType]])
end;
var
PancakesPlate: TStack<TPancake>;
Pancake: TPancake;
begin
WriteLn('Working with TStack - pancakes');
WriteLn;
// "Create" a plate of pancakes
PancakesPlate := TStack<TPancake>.Create;
// Bake some pancakes
// Push - puts items on the stack
PancakesPlate.Push(TPancake.Create(ptMeat));
PancakesPlate.Push(TPancake.Create(ptCherry));
PancakesPlate.Push(TPancake.Create(ptCherry));
PancakesPlate.Push(TPancake.Create(ptCurds));
PancakesPlate.Push(TPancake.Create(ptMeat));
// Eating some pancakes
// Pop - removes an item from the stack
Pancake := PancakesPlate.Pop;
Writeln(Format('Ate a pancake (Pop): %s', [Pancake.ToString]));
// Extract - similar to Pop, but causes in OnNotify
// Action = cnExtracted instead of cnRemoved
Pancake := PancakesPlate.Extract;
Writeln(Format('Ate a pancake (Extract): %s', [Pancake.ToString]));
// What is the last pancake?
// Peek - returns the last item, but does not remove it from the stack
Writeln(Format('Last pancake: %s', [PancakesPlate.Peek.ToString]));
// Show the remaining pancakes
Writeln;
Writeln(Format('Total pancakes: %d', [PancakesPlate.Count]));
for Pancake in PancakesPlate do
Writeln(Pancake.ToString);
// Eat up all
// Clear - clears the stack
PancakesPlate.Clear;
FreeAndNil(PancakesPlate);
Readln;
end.
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