Delphi程序，已知机器码是:558BEC 要求反转为: EC8B55

试题分析：
已知机器码是:558BEC
要求反转为: EC8B55
//第1次 总长度-1-0
//第2次 总长度-1-2
//第3次 总长度-1-2-2
{
所以：
用了下面的自定义
uses
StrUtils;

function cal(n: integer): integer;
begin
result := 2 * n;
end;
再弹框测试得到中间值是否正确，不断修改程序达到预期
}
//使用右面这个函数来截取: MidStr(字符串，开始位置，长度数量)

 

完整实现代码如下：

unit Unit3;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
  System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs,
  Vcl.StdCtrls;

type
  TForm3 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    Edit2: TEdit;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private    { Private declarations }
  public    { Public declarations }
  end;

var
  Form3: TForm3;


implementation

{$R *.dfm}

uses
  StrUtils;

function cal(n: integer): integer;
begin
  result := 2 * n;
end;

procedure TForm3.Button1Click(Sender: TObject);
var
  b: Integer;
  A1: string;
begin
  for b := 0 to ((Length(Edit1.Text)) div 2) do
  begin
    if b = ((Length(Edit1.Text)) div 2) then
      break;

    ShowMessage(IntToStr(cal(b)));
    ShowMessage(MidStr(Edit1.Text, Length(Edit1.Text) - 1 - cal(b), 2));
    A1 := MidStr(Edit1.Text, Length(Edit1.Text) - 1 - cal(b), 2);
    Edit2.Text := Edit2.Text + A1;
  end;
end;

procedure TForm3.Button2Click(Sender: TObject);
begin
  ShowMessage(MidStr(Edit1.Text, Length(Edit1.Text) - 1, 2));
  ShowMessage(MidStr(Edit1.Text, Length(Edit1.Text) - 1 - 2, 2));
  ShowMessage(MidStr(Edit1.Text, Length(Edit1.Text) - 1 - 2 - 2, 2));
end;