Essential things to remember from today's class (class 9, 20th September)

How the Floyd-Warshal algorithm works,
   how it could be implemented,
   what it does for us.

How to make use of floating point infinity.

How to use "od" to inspect a non-text file.

The things you can do with C++ istreams and ostreams.
   As with strings, no need to memorise all the details, but you must be
   aware of what exists, and the details of the most important operations.