foo.c: In function 'main':
foo.c:14:9: warning: 'ch' is used uninitialized [-Wuninitialized]
   14 |         scanf(ch);
      |         ^~~~~~~~~
In file included from /nix/store/y8wfrgk7br5rfz4221lfb9v8w3n0cnyd-glibc-2.37-8-dev/include/features.h:491,
                 from /nix/store/y8wfrgk7br5rfz4221lfb9v8w3n0cnyd-glibc-2.37-8-dev/include/bits/libc-header-start.h:33,
                 from /nix/store/y8wfrgk7br5rfz4221lfb9v8w3n0cnyd-glibc-2.37-8-dev/include/stdio.h:27,
                 from foo.c:1:
/nix/store/y8wfrgk7br5rfz4221lfb9v8w3n0cnyd-glibc-2.37-8-dev/include/stdio.h:437:12: note: by argument 1 of type 'const char * restrict' to 'scanf' declared here
  437 | extern int __REDIRECT (scanf, (const char *__restrict __format, ...),
      |            ^~~~~~~~~~
foo.c:13:14: note: 'ch' declared here
   13 |         char ch[100000], sh[100000];
      |              ^~

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