/in/foo.cc: In function 'char cmp(char, char)':
/in/foo.cc:33:13: warning: array subscript has type 'char' [-Wchar-subscripts]
     if(nei[a] > wai[b]) return '>';
             ^
/in/foo.cc:33:22: warning: array subscript has type 'char' [-Wchar-subscripts]
     if(nei[a] > wai[b]) return '>';
                      ^
/in/foo.cc:34:18: warning: array subscript has type 'char' [-Wchar-subscripts]
     else if(nei[a] == wai[b]) return '=';
                  ^
/in/foo.cc:34:28: warning: array subscript has type 'char' [-Wchar-subscripts]
     else if(nei[a] == wai[b]) return '=';
                            ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:105:5: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
     gets(str1);
     ^~~~
In file included from /usr/include/c++/6/cstdio:42:0,
                 from /usr/include/c++/6/ext/string_conversions.h:43,
                 from /usr/include/c++/6/bits/basic_string.h:5417,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 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:105:14: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
     gets(str1);
              ^
In file included from /usr/include/c++/6/cstdio:42:0,
                 from /usr/include/c++/6/ext/string_conversions.h:43,
                 from /usr/include/c++/6/bits/basic_string.h:5417,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 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:116:9: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
         gets(str2);
         ^~~~
In file included from /usr/include/c++/6/cstdio:42:0,
                 from /usr/include/c++/6/ext/string_conversions.h:43,
                 from /usr/include/c++/6/bits/basic_string.h:5417,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 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:116:18: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
         gets(str2);
                  ^
In file included from /usr/include/c++/6/cstdio:42:0,
                 from /usr/include/c++/6/ext/string_conversions.h:43,
                 from /usr/include/c++/6/bits/basic_string.h:5417,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 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: In function 'long long int calculate(long long int, long long int, char)':
/in/foo.cc:30:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/tmp/cc6VCbP9.o: In function `main':
foo.cc:(.text.startup+0xa2): warning: the `gets' function is dangerous and should not be used.