/in/foo.cc: In function 'int main()':
/in/foo.cc:11:26: error: 'cin' was not declared in this scope
     for(int i=0;i<n;i++) cin>>a[i];
                          ^~~
/in/foo.cc:11:26: 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:23:9: error: 'cin' was not declared in this scope
         cin>>b;
         ^~~
/in/foo.cc:23:9: 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:47:9: error: 'cout' was not declared in this scope
         cout<<count<<" ";
         ^~~~
/in/foo.cc:47:9: 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
                  ^~~~