/in/foo.cc: In function 'int main()':
/in/foo.cc:8:2: error: 'cin' was not declared in this scope
  cin>>a>>b>>c>>d;
  ^~~
/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:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^~~
/in/foo.cc:9:2: error: 'cout' was not declared in this scope
  cout<<a<<' '<<b<<' '<<fixed<<setprecision(6)<<c<<' '<<d;
  ^~~~
/in/foo.cc:9:2: 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:9:24: error: 'fixed' was not declared in this scope
  cout<<a<<' '<<b<<' '<<fixed<<setprecision(6)<<c<<' '<<d;
                        ^~~~~
/in/foo.cc:9:24: note: suggested alternative:
In file included from /usr/include/c++/6/ios:42:0,
                 from /usr/include/c++/6/istream:38,
                 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/bits/ios_base.h:1041:3: note:   'std::fixed'
   fixed(ios_base& __base)
   ^~~~~
/in/foo.cc:9:45: error: 'setprecision' was not declared in this scope
  cout<<a<<' '<<b<<' '<<fixed<<setprecision(6)<<c<<' '<<d;
                                             ^
/in/foo.cc:9:45: note: suggested alternative:
In file included from /usr/include/x86_64-linux-gnu/c++/6/bits/stdc++.h:72:0,
                 from /in/foo.cc:1:
/usr/include/c++/6/iomanip:195:3: note:   'std::setprecision'
   setprecision(int __n)
   ^~~~~~~~~~~~