unit1.~pas

本光盘是《Delphi 7应用教程》一书的配套光盘

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    Edit1: TEdit;
    Label2: TLabel;
    Edit2: TEdit;
    Button1: TButton;
    Label3: TLabel;
    Label4: TLabel;
    Label5: TLabel;
    Edit3: TEdit;
    Edit4: TEdit;
    Label6: TLabel;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
procedure kc51(var x,y:Real);
var
  t:Real;
begin
  if x<y then
    begin   //如果x<y就交换它们的值
      t:=x;
      x:=y;
      y:=t;
    end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  a,b:Real;
begin
  a:=StrToFloat(Edit1.Text);
  b:=StrToFloat(Edit2.Text);
  kc51(a,b);//调用通用过程比较a和b的大小，如果前者小于后者就交换
  Edit3.Text:=FloatToStr(a);
  Edit4.Text:=FloatToStr(b);
end;

end.