unit1.pas

来自「Delphi函数参考大全的CD」· PAS 代码 · 共 39 行

unit Unit1;

interface

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

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

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
  if Sign(StrToFloat(Edit1.Text))= -1 Then
    ShowMessage('为负数')
  else if Sign(StrToFloat(Edit1.Text))= 0 then
    ShowMessage('为零')
  else
    ShowMessage('为正数');
end;

end.