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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 TQueueProject;
{$MODE DELPHI}
{$APPTYPE CONSOLE}
uses
SysUtils, Generics.Collections;
type
// This is FreeSpaaarta! versions =)
TSpartaVersion = (svFreeSparta, svBasic, svStarter, svProfessional);
TCustomer = record
strict private
const
SV_NAMES: array [TSpartaVersion] of string =
('FreeSparta', 'Basic', 'Starter', 'Professional');
public
var
SpartaVersion: TSpartaVersion;
class function Create(SpartaVersion: TSpartaVersion): TCustomer; static;
function ToString: string;
end;
class function TCustomer.Create(SpartaVersion: TSpartaVersion): TCustomer;
begin
Result.SpartaVersion := SpartaVersion;
end;
function TCustomer.ToString: string;
begin
Result := Format('Sparta %s', [SV_NAMES[SpartaVersion]])
end;
var
CustomerQueue: TQueue<TCustomer>;
Customer: TCustomer;
begin
WriteLn('Working with TQueue - buy FreeSparta.com');
WriteLn;
// "Create" turn in sales
CustomerQueue := TQueue<TCustomer>.Create;
// Add a few people in the queue
// Enqueue - puts the item in the queue
CustomerQueue.Enqueue(TCustomer.Create(svFreeSparta));
CustomerQueue.Enqueue(TCustomer.Create(svBasic));
CustomerQueue.Enqueue(TCustomer.Create(svBasic));
CustomerQueue.Enqueue(TCustomer.Create(svBasic));
CustomerQueue.Enqueue(TCustomer.Create(svStarter));
CustomerQueue.Enqueue(TCustomer.Create(svStarter));
CustomerQueue.Enqueue(TCustomer.Create(svProfessional));
CustomerQueue.Enqueue(TCustomer.Create(svProfessional));
// Part of customers served
// Dequeue - remove an element from the queue
// btw if TQueue is TObjectQueue also call Free for object
Customer := CustomerQueue.Dequeue;
Writeln(Format('Sold (Dequeue): %s', [Customer.ToString]));
// Extract - similar to Dequeue, but causes in OnNotify
// Action = cnExtracted instead cnRemoved
Customer := CustomerQueue.Extract;
Writeln(Format('Sold (Extract): %s', [Customer.ToString]));
// For what came next buyer?
// Peek - returns the first element, but does not remove it from the queue
Writeln(Format('Serves customers come for %s',
[CustomerQueue.Peek.ToString]));
// The remaining buyers
Writeln;
Writeln(Format('Buyers left: %d', [CustomerQueue.Count]));
for Customer in CustomerQueue do
Writeln(Customer.ToString);
// We serve all
// Clear - clears the queue
CustomerQueue.Clear;
FreeAndNil(CustomerQueue);
Readln;
end.
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