/in/foo.cc:7:7: error: 'int time' redeclared as different kind of symbol
 int n,time;
       ^~~~
In file included from /usr/include/pthread.h:24:0,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/gthr-default.h:35,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/gthr.h:148,
                 from /usr/include/c++/6/ext/atomicity.h:35,
                 from /usr/include/c++/6/bits/ios_base.h:39,
                 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/time.h:192:15: note: previous declaration 'time_t time(time_t*)'
 extern time_t time (time_t *__timer) __THROW;
               ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:12:5: error: no match for 'operator>>' (operand types are 'std::istream {aka std::basic_istream<char>}' and 'time_t(time_t*) throw () {aka long int(long int*) throw ()}')
  cin>>time;
  ~~~^~~~~~
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:120:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::basic_istream<_CharT, _Traits>::__istream_type& (*)(std::basic_istream<_CharT, _Traits>::__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
       operator>>(__istream_type& (*__pf)(__istream_type&))
       ^~~~~~~~
/usr/include/c++/6/istream:120:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: error: invalid conversion from 'time_t (*)(time_t*) throw () {aka long int (*)(long int*) throw ()}' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&) {aka std::basic_istream<char>& (*)(std::basic_istream<char>&)}' [-fpermissive]
  cin>>time;
       ^~~~
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:124:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::basic_istream<_CharT, _Traits>::__ios_type& (*)(std::basic_istream<_CharT, _Traits>::__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>; std::basic_istream<_CharT, _Traits>::__ios_type = std::basic_ios<char>] <near match>
       operator>>(__ios_type& (*__pf)(__ios_type&))
       ^~~~~~~~
/usr/include/c++/6/istream:124:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: error: invalid conversion from 'time_t (*)(time_t*) throw () {aka long int (*)(long int*) throw ()}' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&) {aka std::basic_ios<char>& (*)(std::basic_ios<char>&)}' [-fpermissive]
  cin>>time;
       ^~~~
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:131:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(std::ios_base& (*)(std::ios_base&)) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
       operator>>(ios_base& (*__pf)(ios_base&))
       ^~~~~~~~
/usr/include/c++/6/istream:131:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: error: invalid conversion from 'time_t (*)(time_t*) throw () {aka long int (*)(long int*) throw ()}' to 'std::ios_base& (*)(std::ios_base&)' [-fpermissive]
  cin>>time;
       ^~~~
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:168:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
       operator>>(bool& __n)
       ^~~~~~~~
/usr/include/c++/6/istream:168:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: warning: the address of 'time_t time(time_t*)' will always evaluate as 'true' [-Waddress]
  cin>>time;
       ^~~~
/in/foo.cc:12:7: error: invalid initialization of non-const reference of type 'bool&' from an rvalue of type 'bool'
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:172:7: note: candidate: std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>] <near match>
       operator>>(short& __n);
       ^~~~~~~~
/usr/include/c++/6/istream:172:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: error: invalid conversion from 'time_t (*)(time_t*) throw () {aka long int (*)(long int*) throw ()}' to 'short int' [-fpermissive]
  cin>>time;
       ^~~~
/in/foo.cc:12:7: error: cannot bind rvalue '(short int)time' to 'short int&'
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:175:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
       operator>>(unsigned short& __n)
       ^~~~~~~~
/usr/include/c++/6/istream:175:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: error: invalid conversion from 'time_t (*)(time_t*) throw () {aka long int (*)(long int*) throw ()}' to 'short unsigned int' [-fpermissive]
  cin>>time;
       ^~~~
/in/foo.cc:12:7: error: cannot bind rvalue '(short unsigned int)time' to 'short unsigned int&'
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:179:7: note: candidate: std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>] <near match>
       operator>>(int& __n);
       ^~~~~~~~
/usr/include/c++/6/istream:179:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: error: invalid conversion from 'time_t (*)(time_t*) throw () {aka long int (*)(long int*) throw ()}' to 'int' [-fpermissive]
  cin>>time;
       ^~~~
/in/foo.cc:12:7: error: cannot bind rvalue '(int)time' to 'int&'
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:182:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
       operator>>(unsigned int& __n)
       ^~~~~~~~
/usr/include/c++/6/istream:182:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: error: invalid conversion from 'time_t (*)(time_t*) throw () {aka long int (*)(long int*) throw ()}' to 'unsigned int' [-fpermissive]
  cin>>time;
       ^~~~
/in/foo.cc:12:7: error: cannot bind rvalue '(unsigned int)time' to 'unsigned int&'
In file included from /usr/include/c++/6/iostream:40:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/istream:186:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
       operator>>(long& __n)
       ^~~~~~~~
/usr/include/c++/6/istream:186:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:7: error: invalid conversion from 'time_t (*)(time_t*) thr