/in/foo.cc: In function 'int main()':
/in/foo.cc:12:12: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type {aka std::basic_istream<char>}' and 'const char [2]')
   cin>>a[i]>>" ";
   ~~~~~~~~~^~~~~
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/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++/7/istream:168:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: cannot bind non-const lvalue reference of type 'bool&' to an rvalue of type 'bool'
   cin>>a[i]>>" ";
              ^~~
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/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++/7/istream:172:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const char*' to 'short int' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(short int)((const char*)" ")' to 'short int&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/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++/7/istream:175:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const char*' to 'short unsigned int' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(short unsigned int)((const char*)" ")' to 'short unsigned int&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/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++/7/istream:179:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const char*' to 'int' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(int)((const char*)" ")' to 'int&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/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++/7/istream:182:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const char*' to 'unsigned int' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(unsigned int)((const char*)" ")' to 'unsigned int&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/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++/7/istream:186:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const char*' to 'long int' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(long int)((const char*)" ")' to 'long int&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/istream:190:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long 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 long& __n)
       ^~~~~~~~
/usr/include/c++/7/istream:190:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const char*' to 'long unsigned int' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(long unsigned int)((const char*)" ")' to 'long unsigned int&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/istream:195:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long 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 long& __n)
       ^~~~~~~~
/usr/include/c++/7/istream:195:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const char*' to 'long long int' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(long long int)((const char*)" ")' to 'long long int&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/istream:199:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long 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 long long& __n)
       ^~~~~~~~
/usr/include/c++/7/istream:199:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const char*' to 'long long unsigned int' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(long long unsigned int)((const char*)" ")' to 'long long unsigned int&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/istream:235:7: note: candidate: std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; std::basic_istream<_CharT, _Traits>::__istream_type = std::basic_istream<char>] <near match>
       operator>>(void*& __p)
       ^~~~~~~~
/usr/include/c++/7/istream:235:7: note:   conversion of argument 1 would be ill-formed:
/in/foo.cc:12:14: error: invalid conversion from 'const void*' to 'void*' [-fpermissive]
   cin>>a[i]>>" ";
              ^~~
/in/foo.cc:12:14: error: cannot bind rvalue '(void*)((const void*)((const char*)" "))' to 'void*&'
In file included from /usr/include/c++/7/iostream:40:0,
                 from /in/foo.cc:2:
/usr/include/c++/7/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>::__istrea