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

• revision #: <description> (DATESTRING)

We've commenced on our list explorations, implementing some of the core functionality (adding nodes to a list through insertion) as well as some helper functionality to make our list transactions even more effective (creating, displaying, getting node positions, and setting node positions).

In this project, we continue our list implementation by exploring the appending of nodes to a list, searching for nodes within a list, copying a list, displaying a list in reverse, and comparing two lists for equality.

In inc/ is the list header file: list.h

For this project, we're going to be implementing the following functions:

List *append(List *, Node *, Node *);   // append new node into list after specified place
Node *searchlist(List *, char);         // is there a node containing value in list?
List *cplist(List *);                   // duplicate existing list
void  displayb(List *, int);            // display list backwards
uc    compare(List *, List *, ulli *);  // compare two lists for equality

Additionally, the following content has been added, largely to aid with compare() implementation and operation:

typedef struct list            List;    // because we deserve nice things
typedef unsigned long long int ulli;    // short name for biggest space
typedef unsigned char          uc;      // shorter name for smallest space

and:

// return status codes
//
#define CMP_EQUALITY       0x00
#define CMP_L1_NULL        0x01
#define CMP_L1_EMPTY       0x02
#define CMP_L1_UNDEFINED   0x03
#define CMP_L1_GREATER     0x04
#define CMP_L1_LESS        0x08
#define CMP_L2_NULL        0x10
#define CMP_L2_EMPTY       0x20
#define CMP_L2_UNDEFINED   0x30
#define CMP_L2_GREATER     0x40
#define CMP_L2_LESS        0x80

As a suggestion, I'd recommend implementing them in the order listed above, starting with append() and then searchlist(). By doing this, you get to review a bit from the previous weeks before you continue with base functionality, which will help you in your implementation of the other functions.

An important perspective to keep when implementing these list functions is to be mindful of what functionality can be a unit of something else. Do not reinvent the wheel- utilize functions you've written- it will shorten your code, and reduce the chance of error. Plus, that IS the intent.. to have each function be specific and focused on its particular task; to do one thing, and do that one thing extremely well. We can then use them as base units to build more sophisticated functionality.

In this project, append() can be considered that basic operation, where cplist() can be built using append() (along with any other list/node functions from this and previous projects).

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

• append.c - which will house the append function
• cp.c - which will house the list copy function
• search.c - which will house the list search function
• displayb.c - which will handle displaying the list backwards
• compare.c - which will handle comparing two lists for equality

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

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

NOTE: None of these files denote an entire runnable program. These are merely standalone functions. The various programs under the unit/ and app/ directories will use these functions in addition to their application logic to create complete executable programs.

You will also notice there are function prototypes for these list library functions in the list.h header file, located in the inc/ subdirectory, which you'll notice all the related programs you'll be playing with in this project are #includeing.

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

• unit-append.c - unit test for append() library function
• unit-cplist.c - unit test for cplist() library function
• unit-searchlist.c - unit test for searchlist() library function
• unit-displayb.c - unit test for displayb() library function
• unit-compare.c - unit test for compare() 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!

As the layers and complexities rise, narrowing down the source of errors becomes increasingly important.

If unit-insert isn't working, is it because of a problem there, in your insert() function, or in one of the node functions it calls, such as mknode()?

To aid you in your development efforts, you now have the ability to import a working implementation of previous project functions into your current project for the purposes of testing/debugging purposes.

You'll notice that, upon running make help in the base-level Makefile, the following new options appear (about halfway in the middle):

**                                                                    **
** make use-test-reference  - use working implementation object files **
** make use-your-own-code   - use your node implementation code       **
**                                                                    **

In order to make use of it, you'll need to run make use-test-reference from the base of your sll0 project directory, as follows:

lab46:~/src/data/sll1$ make use-test-reference
...
NODE reference implementation in place, run 'make' to build everything.
lab46:~/src/data/sll1$ 

You'll see that final message indicating everything is in place (it automatically runs a make clean for you), and then you can go ahead and build everything with it:

lab46:~/src/data/sll1$ make
...

Debugging: When using the test reference implementation, you will not be able to debug the contents of the test reference implementation functions (the files provided do not have debugging symbols added), so you'll need to take care not to step into these functions (it would be just like stepping into printf(). You can still compile the project with debugging support and debug (as usual) those compiled functions (ie the stack functions).

If you were trying out the reference implementation to verify queue functionality, and wanted to revert back to your own code, it is as simple as:

lab46:~/src/data/sll1$ make use-your-own-code
Local node implementation restored, run 'make clean; make' to build everything.
lab46:~/src/data/sll1$ 

Just to be clear: the reference implementation is not some magic shortcut getting you out of doing this project; it merely gives you a glimpse into how things are working, or should be working, provided your node library is complete and fully functional.

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 functions completed for sll1:

lab46:~/src/data/sll1$ make check
======================================================
=    Verifying Singly-Linked  List Functionality     =
======================================================
    [append] Total:  11, Matches:  11, Mismatches:   0
[searchlist] Total:  11, Matches:  11, Mismatches:   0
    [cplist] Total:  11, Matches:  11, Mismatches:   0
  [displayb] Total:  10, Matches:  10, Mismatches:   0
   [compare] Total:  15, Matches:  15, Mismatches:   0
======================================================
   [RESULTS] Total:  58, Matches:  58, Mismatches:   0
======================================================
lab46:~/src/data/sll1$