delphi 2009 中的泛型

代码文件:

unit Unit1;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, StdCtrls;

type

TForm1 = class(TForm)

Memo1: TMemo;

Button1: TButton;

Button2: TButton;

Button3: TButton;

Button4: TButton;

Button5: TButton;

procedure Button1Click(Sender: TObject);

procedure Button2Click(Sender: TObject);

procedure Button3Click(Sender: TObject);

procedure Button4Click(Sender: TObject);

procedure Button5Click(Sender: TObject);

end;

var

Form1: TForm1;

implementation

{$R *.dfm}

type

TArr = array[0..9] of T; {定义一个泛型数组}

{虽然大家习惯用 T 来泛指其他类型, 但使用其他合法的标识符也是可以的}

{用作 Integer}

procedure TForm1.Button1Click(Sender: TObject);

var

Arr: TArr;

i: Integer;

begin

for i := Low(Arr) to High(Arr) do

Arr[i] := i * i;

Memo1.Clear;

for i := Low(Arr) to High(Arr) do

Memo1.Lines.Add(Format('Arr[%d] = %d', [i, Arr[i]]));

end;

{用作 string}

procedure TForm1.Button2Click(Sender: TObject);

var

Arr: TArr;

i: Integer;

begin

for i := Low(Arr) to High(Arr) do

Arr[i] := StringOfChar(Char(i+97), 3);

Memo1.Clear;

for i := Low(Arr) to High(Arr) do

Memo1.Lines.Add(Format('Arr[%d] = %s', [i, Arr[i]]));

end;

{用作 Single}

procedure TForm1.Button3Click(Sender: TObject);

var

Arr: TArr;

i: Integer;

begin

for i := Low(Arr) to High(Arr) do

Arr[i] := 100 / (i+1);

Memo1.Clear;

for i := Low(Arr) to High(Arr) do

Memo1.Lines.Add(Format('Arr[%d] = %f', [i, Arr[i]]));

end;

{用作记录 TPoint}

procedure TForm1.Button4Click(Sender: TObject);

var

Arr: TArr;

i: Integer;

begin

for i := Low(Arr) to High(Arr) do

Arr[i] := Point(i, i*2);

Memo1.Clear;

for i := Low(Arr) to High(Arr) do

Memo1.Lines.Add(Format('Arr[%d] = (%d,%d)', [i, Arr[i].X, Arr[i].Y]));

end;

{用作类 TButton}

procedure TForm1.Button5Click(Sender: TObject);

var

Arr: TArr;

i: Integer;

begin

for i := Low(Arr) to High(Arr) do

begin

Arr[i] := TButton.Create(Self);

Arr[i].Name := Concat('Btn', IntToStr(i+1));

end;

Memo1.Clear;

for i := Low(Arr) to High(Arr) do

Memo1.Lines.Add(Format('Arr[%d] is %s', [i, Arr[i].Name]));

for i := Low(Arr) to High(Arr) do Arr[i].Free;

end;

end.

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