foo.c: In function 'Diff':
foo.c:4:27: warning: unused variable 'o' [-Wunused-variable]
    4 |         int c,i=0,m=0,n=0,o=0;
      |                           ^
foo.c: In function 'main':
foo.c:23:9: warning: 'gets' is deprecated [-Wdeprecated-declarations]
   23 |         gets(s1);
      |         ^~~~
In file included from foo.c:1:
/nix/store/y8wfrgk7br5rfz4221lfb9v8w3n0cnyd-glibc-2.37-8-dev/include/stdio.h:605:14: note: declared here
  605 | extern char *gets (char *__s) __wur __attribute_deprecated__;
      |              ^~~~
foo.c:24:9: warning: 'gets' is deprecated [-Wdeprecated-declarations]
   24 |         gets(s2);
      |         ^~~~
/nix/store/y8wfrgk7br5rfz4221lfb9v8w3n0cnyd-glibc-2.37-8-dev/include/stdio.h:605:14: note: declared here
  605 | extern char *gets (char *__s) __wur __attribute_deprecated__;
      |              ^~~~
foo.c: In function 'Diff':
foo.c:18:12: warning: 'c' may be used uninitialized [-Wmaybe-uninitialized]
   18 |     return c;
      |            ^
foo.c:4:13: note: 'c' was declared here
    4 |         int c,i=0,m=0,n=0,o=0;
      |             ^
/nix/store/74y3751gsixaz9797ib0hp7c658sp1y5-binutils-2.40/bin/ld: /tmp/ccKjoPd9.o: in function `main':
foo.c:(.text.startup+0xb): warning: the `gets' function is dangerous and should not be used.

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