It's obviously not Linux, which supports Unicode as intended, and prints this correctly (see for example http://ideone.com/2chLsG )
If this is Windows, your best bet is to go wide (it's also a safe bet on Linux, and other systems): std::wcout << L"É\n";, except that on Visual Studio you'd have to issue the Microsoft-specific _setmode(_fileno(stdout), _O_WTEXT); (see MSDN for the necessary #include files).
Other compilers/platforms probably have their own ways.