/in/foo.cc:2:1: error: 'cin' does not name a type
 cin>>a>>b>>c>>d;
 ^~~
/in/foo.cc:3:1: error: 'cout' does not name a type
 cout <<a*b*c*d;
 ^~~~
/in/foo.cc:4:1: error: expected unqualified-id before 'return'
 return 0;
 ^~~~~~