foo.c: In function 'main':
foo.c:7:9: warning: 'gets' is deprecated [-Wdeprecated-declarations]
    7 |         gets(str);
      |         ^~~~
In file included from foo.c:1:
/nix/store/ck17nf5q2m51d9jpkpsirx91s64vh202-glibc-2.35-163-dev/include/stdio.h:605:14: note: declared here
  605 | extern char *gets (char *__s) __wur __attribute_deprecated__;
      |              ^~~~
foo.c:26:12: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
   26 |         if (c == '+')
      |            ^
/nix/store/dpxy5cr7cm0nch0qvq2qygs9jwnmhiy5-binutils-2.38/bin/ld: /tmp/cc1pVdoX.o: in function `main':
foo.c:(.text.startup+0x8): warning: the `gets' function is dangerous and should not be used.

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