using namespace std;
namespace ui { class CClass; } // Expected to stay as-is
namespace ui::dlg { class CClassDlg; } // Expected to stay as-is (new in C++17)
namespace ui { // Brace should be on the next line
class CClass1; // Should be indented
class CClass2;
class CClass3;
class CClass4;
class CClass5;
class CClass6;
class CClass7;
}