(last revised Saturday May  19, 10:10 AM)

1)  There were some errors in the original version of assignment 3.
These have now been fixed.   The errors were

a) In  Figure  1  the edge (4,1) was missing.  It has now been added.
     The commands    g.setEdge(4,1);      and   g.delEdge(4,1); were
      added to the beginning of the example program in the assignmnet

b) In file  graph.h       virtual bool sibling(int i, int j);     was changed
      to                            virtual bool sibling(int i, int j)=0;

c) The original output for   cout <<g.sibling(0,2); in the  example program
      was incorrect.  It has now been fixed (to output 0)

2)  Q.  Can we change  the file graph.h  by adding new public
or private members?
A. No.  We will be compiling the code using our graph.h
(the one provided in the assignment description).  So,
even if you added members to your own version of graph.h
it would not help since we would not compile the code with it.

3)  Q. I am having difficulty compiling graphm.cpp and graphl.cpp
together using the same driver file.  What can I  do?
A. When we compile the code we will use different drivers
to test the  graphl and graphm classes so this problem will not
occur during our testing (but it would still be good if you can
fix this).

4) Q. Do we have to write constructors for graphm and graphl?
A.  You need to write constructors for graphm and graphl to
replace the ABS graph  constructor.  That is,  the constructors should
have the prototypes:
graphm (int v);  // Create a graph with   v  vertices
graphl (int v);    //Create a graph with   v  vertices

We do not require that you write explicit destructors.  But,  you
are not allowed to have memory leakage in your programs.  So,
if your implementations use dynamically allocated memory, then
you must provide destructors that deallocate them.

5) Q. Can I use   deques   instead of   lists  in graphl?
A. No.  You must use some form of list in graphl, either
the STL provided   list  or one that you've written yourself.
The   deque   class does not provide fast  insertion/deletion
from the middle of the container and would therefore be very
slow when updating large graphs.

6) Q. Can you provide a test driver for the programs?
A.    HERE is a test  driver (and its  Output (revised May 18,2001) .
Please note that the driver only tests graphm.  To test graphl
replace the fourth line in the driver --  #include "graphm.h" --
by    #include "graphl.h"

7) Q. The original specifications for where to place the program looked strange. Were they wrong?
A. Yes.  there was a mistake in the original specifications. They have just been fixed and what is now written on the assignment specification page is correct.  Your five files should actually be placed in directory  ~/comp151/assign3