PROGRAM DESCRIPTION
- As each node is drawn, it's coordinates are stored in an array. 
Drawing lines and additional nodes is straightforward.
- When a user selects delete and clicks on the canvas, the program
evaluates first whether the user has clicked inside the arc of one of
the nodes.  If the click occurs outside the arc of all nodes, then
nothing happens.  If the user clicks inside the arc, then the 
program evaluats for the node center that is the smalles radial
distance from the button press and then selects this node. This
node is replaced by the last node in the array and then the entire 
graph is cleared and re-drawn
- The curses interface obtains the size of the terminal display area
and then uses the ratio between that display and the 400 pixel by
400 pixel drawing canvas to place the node coordinates in the 
appropriate location.
- When deleting nodes of the curses interface the program calculates
the length of the text originally printed for the node and then
deletes exactly that amount of text on the curses interface.
- The modal interface is supported by a variable "mode" which is 
used throughout the functions to track whether in draw or delete
mode and also when quitting or erasing and to perform the appropriate
action.

FILES
- dcg.c       This is a c++ file that contains motif, xlib and curses code
- makefile    Makefile to compile the dcg.c code to output file dcg  
- dcg_environment    Contains motif interface environment entries       

SPECIAL INSTRUCTIONS TO GRADE
- Type "dcg" to run the program once compiled
- The program assumes that you have set your DISPLAY to an Xwin output
The shell script setenv DISPLAY `who am i | cut -d"(" -f2| cut -d"." -f1`:0
does not work if you are logging-in like I was using remote desktop.
Instead, I selected the option to allow X11 tunneling in SSH and when
the dcg program runs it opens an xwin display connected to that terminal.