1.

>  How do you pass the_text_file [this is the name of an input file
> stream] to a function?  I tried 
> calling it in a function, but the compiler tells me it's not declared.
> I tried passing it as a parameter, but I got a whole slew of confusing
> error messages about the stream.

This is a  C++ thing, not an objectcenter bug.  First the extremely
short answer:
   On assignment 1, just do your stream I/O inside main, or else
   define the_text_file as a global variable.

Now the slightly longer answer:
   If you want to pass a stream to a function, you need to either pass a
pointer to it or pass it by reference.  Normally,  I think it's a bad
idea to pass by reference (see the end of this message for more on that)
but in this case, it makes things a bit cleaner.  For instance, you can
do:

void myfunction(ifstream *p)
{
  word_t w;
  *p >> w;
}

and call it with
myfunction(&the_text_file);

or,  you can define myfunction like:

void myfunction(ifstream &str)
{
  word_t w;
  str >> w;
}
and then call it with
myfunction(the_text_file);

Now the really long answer:
   First, what's a stream?  Well, a stream is a "class", which is like a
struct.  It holds inside it a bunch of bookkeeping information about how
much you have read in and other pieces of information.  If you passed a
stream into a function by value, weird things would happen since the
function you passed it to would have a COPY of the stream.  So, if the
function  read in a few words and then returned, your original stream
wouldn't  have its bookkeeping information consistent any more.  For
this reason, C++ does not allow you to make copies of the stream, and in
particular to pass it by value.  So, you have to either pass a pointer
or a reference.

                Avrim Blum


ps: here is why in general I don't like pass by reference.  In C, if you
have two ints a and b, and you call foo(a,b), maybe foo will crash your
program but at least you can be sure it won't change the values of a and
b. In C++, you can't be so sure, since maybe they are "reference"
arguments to foo.  You need to check the function prototype of foo to be
sure.  This makes it harder to debug code, since it's easy to forget
when you're scanning through the program.

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