China DOS Union

How to use a FOR loop to "simplify" the following batch processing to write the drive letters in findd.txt to the drive.txt file (for WBAT to call)?

find "C:\" findd.txt >nul
if not errorlevel 1 echo C:>>drive.txt
find "D:\" findd.txt >nul
if not errorlevel 1 echo D:>>drive.txt
find "E:\" findd.txt >nul
....

Re GOTOmsdos: Although using a FOR loop is also achievable, I do not recommend using it because it is not flexible in controlling internal processes; I suggest you use a command-line loop. I once wrote several similar programs for兄 walu, and you can refer to and modify them using the following links:
http://bbs.cn-dos.net/dispbbs.asp?boardid=12&id=9637
http://bbs.cn-dos.net/dispbbs.asp?boardid=9&id=11963
http://bbs.cn-dos.net/dispbbs.asp?boardid=12&id=14552
http://bbs.cn-dos.net/dispbbs.asp?BoardID=9&ID=14512

In pure DOS, it can't be nested like this. Looking at the building's program, it should be under pure DOS, so SHIFT should be used.

Thanks for the reminder, just use SHIFT with a parameter. It's really difficult with FOR!drive.bat:
@echo off
:loop
if "%1"=="" goto end
find "%1" findd.txt>nul
if not errorlevel 1 echo %1>>drive.txt
shift
goto loop
:end
Input: drive c: d: e: ....