/in/foo.cc: In function 'int main()':
/in/foo.cc:18:38: error: wrong number of template arguments (0, should be 1)
     sort(v.begin(), v.end(), greater<>());
                                      ^
In file included from /usr/include/c++/6/string:48:0,
                 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/c++/6/bits/stl_function.h:371:12: note: provided for 'template<class _Tp> struct std::greater'
     struct greater : public binary_function<_Tp, _Tp, bool>
            ^~~~~~~