foo.cc: In function ‘int main()’:
foo.cc:9:13: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations]
    9 |         gets(a);
      |         ~~~~^~~
In file included from /nix/gcc-14-20241116/include/c++/14-20241116/cstdio:42,
                 from /nix/gcc-14-20241116/include/c++/14-20241116/ext/string_conversions.h:45,
                 from /nix/gcc-14-20241116/include/c++/14-20241116/bits/basic_string.h:4154,
                 from /nix/gcc-14-20241116/include/c++/14-20241116/string:54,
                 from /nix/gcc-14-20241116/include/c++/14-20241116/bitset:52,
                 from stdc++.h:52:
/nix/glibc-2.40-66-dev/include/stdio.h:667:14: note: declared here
  667 | extern char *gets (char *__s) __wur __attribute_deprecated__;
      |              ^~~~
/nix/binutils-2.43.1/bin/ld: /tmp/ccGv0JkM.o: in function `main':
foo.cc:(.text.startup+0x18): warning: the `gets' function is dangerous and should not be used.