/in/foo.cc:3:10: error: 'int time' redeclared as different kind of symbol
 int next,time;
          ^~~~
In file included from /usr/include/c++/6/ctime:42:0,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:49,
                 from /in/foo.cc:1:
/usr/include/time.h:192:15: note: previous declaration 'time_t time(time_t*)'
 extern time_t time (time_t *__timer) __THROW;
               ^~~~