swap 交换

IT_ZZW035

EDIT1.TEXT:='1';
EDIT2.TEXT:='2';
SWAP后应该是
EDIT1.TEXT:='2'
EDIT2.TEXT:='1'
根据给的源码结果总是
EDIT1.TEXT:='2'
EDIT2.TEXT:='2'
求解
源码如下 ：
unit Unit1;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Swap_fun(var str_a:String; str_b:String);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
var
  Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
var
  str1: String;
  str2: String;
  temp: String;
begin
  str1:= Edit1.Text;
  str2:= Edit2.Text;
  Swap_fun(str1, str2);
  Edit1.Text:= str1;
  Edit2.Text:= str2;
end;
procedure tform1.Swap_fun(var str_a:String;str_b:String);
var
temp:string;
begin
  temp:= str_a;
  str_a:= str_b;
  str_b:= temp;
end;
end.

comeheres

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暂时不给你答案，自己看下下面的知识点

bj584767285

支持一下！

tlwangxd

每二个参数引用前边没有加VAR，或这样写：Var str_a ,str_b:String