Try…Finally…End实例

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  i: ^integer;
  res, y: double;
begin
  try
    new(i);                              //申请内存给动态变量，并令i指针指向此内存
    i^ := strtoint(edit1.Text);
    y := pi;
    res := y/i^;
    label1.Caption := 'PAI div' + inttostr(i^) + ' = ' + floattostr(res);
  finally                                //此区必定会执行
    showmessage('现在释放i^所占内存');
    dispose(i);                          //释放i变量指向的实体，避免占用内存空间
  end;
end;

end.