>>640
gnuWin32 用の rev.exe が欲しいなら、書き起こさなくともutil-linux-ng パッケージに入っていると思うが…

util-linux-ng for Windows
http://gnuwin32.sourceforge.net/packages/util-linux-ng.htm

Util-Linux contains miscellaneous utilities:
col: filter reverse line feeds from input
colcrt: filter nroff output for CRT previewing
colrm: remove columns from a file
ddate: converts Gregorian dates to Discordian dates
getopt: parse command options (enhanced)
hexdump: ascii, decimal, hexadecimal, octal dump
line: read one line
rename: rename files
rev: reverse lines of a file or files　←
tailf: follow the growth of a log file
whereis: locate the binary, source, and manual page files for a command

作りたいというなら類似のsampleソースはｺﾞﾏﾝと転がっとるし

C reverse string rev.c strrev - Google 検索
https://www.google.com/search?q=C+reverse+string+rev.c+strrev

C program to reverse a string | Programming Simplified
https://www.programmingsimplified.com/c-program-reverse-string

C_69 C Program to Reverse a String | with strrev() and without strrev() function - YouTube
https://www.youtube.com/watch?v=530jWnBMD2M

…　好きにしんしゃい