The elder brother gave pointers to the specific meaning of the code of the header file.

zl19851215

#if! defined (AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_)
#define AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_

#if _MSC_VER> 1000
#pragma once
#endif // _MSC_VER> 1000
// AddSwitchDlg.h: header file
//

xietao405

#if! defined (AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_)
#define AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_

If this macro AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_ is not defined, execute the following statement
Until the corresponding #endif

#if _MSC_VER> 1000 If _MSC_VER> 1000 then add a sentence #pragma once otherwise do n’t add

ngchfc

#if! defined (AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_)
#define AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_
-------------------------------------------------- ----------------
In order to avoid repeated references to header files

#if _MSC_VER> 1000
#pragma once
#endif // _MSC_VER> 1000
-------------------------------------------------- ----------------
pragma once is only supported by some compilers under WIN32 platform, such as msc. statement only compile once.

I wrote it according to my needs.

zl19851215

#if !defined(AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_)
#define AFX_ADDSWITCHDLG_H__FF1B528B_44B3_4ACD_A66D_739AE81085FB__INCLUDED_
What generated the above two sentences?
Wouldn’t it be written by myself? Compiler generated?