/in/foo.cc: In function 'int main()':
/in/foo.cc:6:2: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(ch);
  ^~~~
In file included from /usr/include/c++/6/cstdio:42:0,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:46,
                 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:6:9: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
  gets(ch);
         ^
In file included from /usr/include/c++/6/cstdio:42:0,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:46,
                 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:11:15: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(l<m&&ch[l]==ch[m])
               ^
/in/foo.cc:11:22: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(l<m&&ch[l]==ch[m])
                      ^
/tmp/cceVuX01.o: In function `main':
foo.cc:(.text.startup+0xc): warning: the `gets' function is dangerous and should not be used.