/in/foo.c: In function 'main':
/in/foo.c:10:2: warning: 'gets' is deprecated [-Wdeprecated-declarations]
  gets(s);
  ^~~~
In file included from /in/foo.c:1:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.c: In function 'cycle':
/in/foo.c:23:7: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(s[i]!=s[j])
       ^
/in/foo.c:23:13: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(s[i]!=s[j])
             ^
/tmp/ccGOva48.o: In function `main':
foo.c:(.text.startup+0x9): warning: the `gets' function is dangerous and should not be used.