/in/foo.cc: In function 'int main()':
/in/foo.cc:12:2: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(s);
  ^~~~
In file included from /usr/include/c++/6/cstdio:42:0,
                 from /in/foo.cc:1:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.cc:12:8: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(s);
        ^
In file included from /usr/include/c++/6/cstdio:42:0,
                 from /in/foo.cc:1:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.cc:13:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (i=0; i<=strlen(s); i++){
            ~^~~~~~~~~~~
/in/foo.cc:16:6: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
   if (s[i]==')') 
      ^
/in/foo.cc:19:6: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
   if (s[i]==']') 
      ^
/tmp/ccxHDsev.o: In function `main':
foo.cc:(.text.startup+0xc): warning: the `gets' function is dangerous and should not be used.