This section will document any updates applied to the project since original release:

• revision #: <description> (DATESTRING)

In this project, we take a step up from our singly linked list implementation- just as the singly-linked list was a step up from the individual nodes as an organizing unit for nodes.

So what does this give us? An organizing unit for lists! I'm calling them “ListGroups” or “GroupOfLists”, and we'll also sneak in true linked list functionality, by adding an “after” pointer to the List struct.

For this project, we need to make a couple modifications to the list struct (which you can also check out in inc/list.h):

struct list {
    Node              *first;           // pointer to start of list
    Node              *last;            // pointer to end of list
    struct list       *after;           // pointer to the next list
    unsigned long int  qty;             // number of nodes in list
};
typedef struct list    List;            // because we deserve nice things

Specifically, we have an after pointer, so that we can point to an entirely separate list, along with a newly added qty variable, which will keep track of the number of nodes in the list.

To implement qty, all list functions that perform manipulations to the list will need to see some updating (insert(), append(), obtain(), and mklist()).

mklist() should also set the list's after pointer to a sane initial state (NULL).

With the updated list struct (and supporting list functions), we can now organize our lists with this new groupoflists struct (typedef'ed to Group for typing convenience).

#ifndef _GROUP_H
#define _GROUP_H
 
#include "list.h"                        // list relies on node to work
 
struct groupoflists {
    List *first;                         // pointer to first list
    List *last;                          // pointer to last list
};
typedef struct groupoflists Group;       // because we deserve nice things
 
Group *mkgroup(void);                    // create/allocate new Group
Group *rmgroup(Group *);                 // clear/deallocate Group
 
Group *linsert(Group *, List *, List *); // add list before given list
Group *lappend(Group *, List *, List *); // add list after given list
Group *lobtain(Group *, List **);        // obtain/disconnect list from group
 
long int  ldisplay(Group *, long int);   // display entire/aspects of list group
 
long int  lgetpos(Group *, List *);      // retrieve position from given node
List     *lsetpos(Group *, long int);    // seek to indicated node in list
 
#endif

You should notice a striking similarity to the core list functionality (a first and a last pointer– only to Lists, and not Nodes), and the presence of Group manipulation and utility functions (appending, inserting, obtaining, displaying, getting/setting position, creating, and removing a group).

This project will test the level of your abstraction skills– for there isn't that much of a conceptual difference between the list functions and the group functions. The more you understand that, the easier this project will be.

In src/list/, you will find 5 new C files:

• obtain.c - which will house the list obtain function (to disconnect nodes from a list)
• clear.c - which will handle clearing (emptying) the list
• rm.c - which will handle deallocating (purging) the list
• swap.c - which will handle swapping two nodes within a list
• sort.c - which will house the list sort function

Take a look at the code there. These are the files that contain functions which will be compiled and archived into the node library (liblist.a) we will be using in this and future projects.

Figure out what is going on, make sure you understand it.

In testing/list/unit/, you will find these new files:

• unit-obtain.c - unit test for obtain() library function
• unit-clearlist.c - unit test for clearlist() library function
• unit-rmlist.c - unit test for rmlist() library function
• unit-swapnode.c - unit test for swapnode() library function
• unit-sortlist.c - unit test for sortlist() library function

These are complete runnable programs (when compiled, and linked against the list library, which is all handled for you by the Makefile system in place).

Of particular importance, I want you to take a close look at:

• the source code to each of these unit tests
  • the purpose of these programs is to validate the correct functionality of the respective library functions
  • follow the logic
  • make sure you understand what is going on
  • ask questions to get clarification!
• the output from these programs once compiled and ran
  • analyze the output
  • make sure you understand what is going on
  • ask questions to get clarification!

Now that we've completed our list functionality, we can use these individual functions to piece together solutions to various everyday problems where a list could be effective. After all, that's a big aspect to learning data structures- they open doors to new algorithms and problem solving capabilities.

Our first endeavor will be that of palindromes (ie words/phrases that, when reversed, spell the same thing).

This implementation will be considered an extra credit opportunity, so as to offer those who have fallen behind (but working to get caught up) a reprieve on some of the credit they've lost.

It is also highly recommended to undertake as it will give you further experience working with these concepts.

To assist you in verifying a correct implementation, a fully working implementation of the node library and list library (up to this point) should resemble the following:

Here is what you should get for the node library:

lab46:~/src/data/sll2$ bin/verify-node.sh 
====================================================
=    Verifying Singly-Linked Node Functionality    =
====================================================
 [mknode] Total:   4, Matches:   4, Mismatches:   0
 [cpnode] Total:   5, Matches:   5, Mismatches:   0
 [rmnode] Total:   2, Matches:   2, Mismatches:   0
====================================================
[RESULTS] Total:  11, Matches:  11, Mismatches:   0
====================================================
lab46:~/src/data/sll2$ 

Here is what you should get for all the functions completed so far in the list library (sll0+sll1+sll2):

lab46:~/src/data/sll2$ bin/verify-list.sh 
======================================================
=     Verifying Singly-Linked List Functionality     =
======================================================
    [mklist] Total:   5, Matches:   5, Mismatches:   0
    [insert] Total:  11, Matches:  11, Mismatches:   0
  [displayf] Total:   4, Matches:   4, Mismatches:   0
    [getpos] Total:   8, Matches:   8, Mismatches:   0
    [setpos] Total:   9, Matches:   9, Mismatches:   0
    [append] Total:  11, Matches:  11, Mismatches:   0
[searchlist] Total:  11, Matches:  11, Mismatches:   0
    [cplist] Total:  11, Matches:  11, Mismatches:   0
  [displayb] Total:   6, Matches:   6, Mismatches:   0
   [compare] Total:   9, Matches:   9, Mismatches:   0
    [obtain] Total:  28, Matches:  28, Mismatches:   0
 [clearlist] Total:   3, Matches:   3, Mismatches:   0
    [rmlist] Total:   3, Matches:   3, Mismatches:   0
  [swapnode] Total:   9, Matches:   9, Mismatches:   0
  [sortlist] Total:  27, Matches:  27, Mismatches:   0
======================================================
   [RESULTS] Total: 155, Matches: 155, Mismatches:   0
======================================================
lab46:~/src/data/sll2$ 

To be successful in this project, the following criteria must be met:

• Project must be submit on time, by the posted deadline.
  • Late submissions will lose 25% credit per day, with the submission window closing on the 4th day following the deadline.
• All code must compile cleanly (no warnings or errors)
  • all requested functions must be implemented in the related library
  • all requested functionality must conform to stated requirements (either on this project page or in comment banner in source code files themselves).
• Executed programs must display in a manner similar to provided output
  • output formatted, where applicable, must match that of project requirements
• Processing must be correct based on input given and output requested
• Output, if applicable, must be correct based on values input
• Code must be nicely and consistently indented (you may use the indent tool)
• Code must be commented
  • Any “to be implemented” comments MUST be removed
    • these “to be implemented” comments, if still present at evaluation time, will result in points being deducted.
  • Sufficient comments explaining the point of provided logic MUST be present
• Any and all functions written must have, at most, 1 return statement
  • points will be lost for solutions containing multiple return statements in a function.
• Track/version the source code in a repository
• Submit a copy of your source code to me using the submit tool (make submit will do this) by the deadline.