/in/foo.cc:2:7: error: expected nested-name-specifier before 'spacename'
 using spacename std;
       ^~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:6:2: error: 'cout' was not declared in this scope
  cout>>i*2>>endl;
  ^~~~
/in/foo.cc:6:2: note: suggested alternative:
In file included from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:75:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^~~~
/in/foo.cc:6:13: error: 'endl' was not declared in this scope
  cout>>i*2>>endl;
             ^~~~
/in/foo.cc:6:13: note: suggested alternative:
In file included from /usr/include/c++/6/istream:39:0,
                 from /usr/include/c++/6/sstream:38,
                 from /usr/include/c++/6/complex:45,
                 from /usr/include/c++/6/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/6/ostream:590:5: note:   'std::endl'
     endl(basic_ostream<_CharT, _Traits>& __os)
     ^~~~
/in/foo.cc:8:2: error: 'cout' was not declared in this scope
  cout>>i*2.2>>endl;
  ^~~~
/in/foo.cc:8:2: note: suggested alternative:
In file included from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:75:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^~~~
/in/foo.cc:8:15: error: 'endl' was not declared in this scope
  cout>>i*2.2>>endl;
               ^~~~
/in/foo.cc:8:15: note: suggested alternative:
In file included from /usr/include/c++/6/istream:39:0,
                 from /usr/include/c++/6/sstream:38,
                 from /usr/include/c++/6/complex:45,
                 from /usr/include/c++/6/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:52,
                 from /in/foo.cc:1:
/usr/include/c++/6/ostream:590:5: note:   'std::endl'
     endl(basic_ostream<_CharT, _Traits>& __os)
     ^~~~