As I was running through the exercises on Worksheet 9, I ran into a couple microsoft bugs. These bugs involve the use of
using namespace std; before declaring 'friend' functions of classes. Weird compiler errors result. This bug was fixed in MSVC++ 6.0's Service Pack 3 and later. You can find that service pack at http://www.microsoft.com/downloads/search.asp

If the computer you're working on does not have this Service Pack installed, and you are not permitted to make such an installation, there is a workaround...

First, remove any instances of
using namespace std; from before your class definition. Note that this means you must now explicitly declare std elements, including cin, cout, cerr, endl, istream, and ostream. In other words, anywhere in your code prior to the using namespace std; line, replace all instances of cin with std::cin, endl with std::endl, ostream with std::ostream, etc etc.

Any questions about these problems, please let me know asap.