/in/foo.cc:2:20: warning: extra tokens at end of #include directive
 #include <iomanip> using namespace std;
                    ^~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:6:2: error: 'cin' was not declared in this scope
  cin>>n;
  ^~~
/in/foo.cc:6:2: note: suggested alternative:
In file included from /in/foo.cc:1:0:
/usr/include/c++/6/iostream:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^~~
/in/foo.cc:11:5: error: 'cout' was not declared in this scope
     cout<<""<<setw(4)<<j*n+i;
     ^~~~
/in/foo.cc:11:5: note: suggested alternative:
In file included from /in/foo.cc:1:0:
/usr/include/c++/6/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^~~~
/in/foo.cc:11:21: error: 'setw' was not declared in this scope
     cout<<""<<setw(4)<<j*n+i;
                     ^
/in/foo.cc:11:21: note: suggested alternative:
In file included from /in/foo.cc:2:0:
/usr/include/c++/6/iomanip:225:3: note:   'std::setw'
   setw(int __n)
   ^~~~
/in/foo.cc:13:2: error: 'cout' was not declared in this scope
  cout<<endl;
  ^~~~
/in/foo.cc:13:2: note: suggested alternative:
In file included from /in/foo.cc:1:0:
/usr/include/c++/6/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^~~~
/in/foo.cc:13:8: error: 'endl' was not declared in this scope
  cout<<endl;
        ^~~~
/in/foo.cc:13:8: note: suggested alternative:
In file included from /usr/include/c++/6/iostream:39:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/ostream:590:5: note:   'std::endl'
     endl(basic_ostream<_CharT, _Traits>& __os)
     ^~~~