Summary of Presentation of February 17, 1999

	We continued with testing of the program for February 12th.  Today,
we developed a simple driver module ( a main function) to do basis path 
testing of the OpenForOutput function.  This main function told the user
which file names to provide to the unit under test since we did not 
have a test harness ( a program that wraps around the unit under test and
provides it with input while capturing all of its output).  
	We did an extensive discussion of streams since students seemed
to lack the necessary understanding from Comp 227-228.  A stream is 
just a sequence of items of unlimited size.  There are input streams
which a program ( C or C++ or many other programming languages) uses 
to get values and output streams onto which a program places values.
One special type of input stream is intended for use with a physical 
file.  This is called an ifstream.  We declare a variable of type 
ifstream such as
	ifstream example;
Then we need to tell the operating system what physical file this stream
will get its values from.  To do that, we open the stream, for example
	example.open("figures");
where figures is a file in the current directory that contains the data 
we want to get.  As a result of the open, the operating system establishes
a connection between our stream variable and the actual physical file. 
The operating system builds and maintains a large, complex set of data
structures to keep track of the correspondence between the stream and
the actual physical file.  The ifstream variable ( example in our example)
has a pointer to these data structures as its value after the open.
	We discussed several input operations on ifstreams including get,
>>, and ignore.  We also discussed output using ofstreams and the <<
operator.
	Students were reminded that they should be reviewing and 
improving their facility with the non object-oriented features of C++ 
since we will be moving to more complex features in a couple of weeks. 
Nine programs are available on this web site to assist students in 
ensuring they understand these features.
	We will be moving on to chapter 18 with the next class period.