CS202 Lab 8 - Dlists

dlist.cpp

Your job is to write dlist.cpp so that it properly implements all of the methods of the Dlist class, as described in the lecture notes on linked data structures.

You are not allowed to have any STL data structures or header files in your implementation -- you may only include <iostream> and "dlist.hpp". The implementation should be as described in the lecture notes: as a circular list with a sentinel node.

The gradescript will test all of the src/dlist_rev_x.cpp programs from the lecture notes, plus the program src/dlist_editor.cpp that I describe below.

You should doublecheck your include/dlist.hpp and make sure that it is the same one as in this lab directory. In particular, you should not use an old one that doesn't have the Next() and Prev() methods.

The list editor

This is yet another command-line program that lets me test your code. There is always a current list that is being edited. The list holds strings that are single words, and the words in a list must be unique.

The program takes a prompt on the command line (use "-" for no prompt). You can see a list of the commands by entering a question mark: 

UNIX> echo '?' | bin/dlist_editor
CLEAR:               This calls the Clear() method, clearing the list.
DESTROY:             This deletes the list and creates a new one with new.
PRINT_FORWARD:       This prints the list, all on one line in the forward direction.
PRINT_REVERSE:       This prints the list, all on one line in the reverse direction.
PRINT_COPY:          This prints the list using a procedure which calls the copy constructor.
PUSH_BACK s:         This calls Push_Back on the string s.
PUSH_FRONT s:        This calls Push_Front on the string s.
POP_BACK:            This calls Pop_Back and prints the string
POP_FRONT:           This calls Pop_Front and prints the string.
ERASE s:             This calls Erase on the pointer to the node that holds string s. 
                     If s is not on the list, this does nothing.
INSERT_BEFORE s1 s2: This calls Insert_Before(s1, d), 
                     where d is the pointer to the node that holds string s2. 
                     If s2 is not on the list, this does nothing.
INSERT_AFTER s1 s2:  This calls Insert_After(s1, d).
EMPTY:               This returns whether the list is empty.
SIZE:                This returns the list's size.
AO:                  This tests the assignment overload by copying to a second list,
                     and then copying back.
?:                   Print these commands.
QUIT:                Exit.
UNIX>
So, for example: 
UNIX> bin/dlist_editor 'Editor>'
Editor> PUSH_BACK a
Editor> PUSH_BACK b
Editor> PUSH_BACK c
Editor> PUSH_BACK d
Editor> PRINT_FORWARD
a b c d
Editor> PUSH_FRONT z
Editor> PRINT_FORWARD
z a b c d
Editor> PRINT_REVERSE
d c b a z
Editor> POP_BACK
d
Editor> POP_FRONT
z
Editor> PRINT_FORWARD
a b c
Editor> SIZE
3
Editor> EMPTY 
No
Editor> INSERT_BEFORE xxx b
Editor> PRINT_FORWARD
a xxx b c
Editor> INSERT_AFTER yyy b
Editor> PRINT_FORWARD
a xxx b yyy c
Editor> ERASE b
Editor> PRINT_FORWARD
a xxx yyy c
Editor> SIZE
4
Editor> CLEAR
Editor> EMPTY
Yes
Editor> PUSH_BACK a
Editor> PRINT_FORWARD
a
Editor> QUIT
UNIX>
Use COPY, DESTROY and AO to test your copy constructor, destructor and assignment overload.