CSC161 2010F, Class 52: Building Stacks and Queues from Arrays

Overview:
* Exam 3
* Review
* Improv Lab

Admin:
* EC for Tuesday's cool movie
* EC for tonight's Latin American Jazz Ensemble Thingy
* EC for collegium compline thingy at the red-door church across the
  street from bucksbaum
  7 pm Sunday night
* EC for freenet sunday
* EC for responsible drinking (or non-drinking) before and after Waltz

Questions:
* I am confused about when to use malloc and when not to.
  * (1) When you are creating a new structure and you want it to
        live beyond the current procedure, you use malloc.
  * (2) You can also allocate with strdup and strndup (and a few other
        functions).  You use these in the same cases.
  * (3) You can use malloc or strdup or strndup for allocating
        strings.
  * (4) You can only use malloc for arrays, structs, 
* Why would you use malloc instead of declaring a global variable?
  * When you are likely to make/need more than one copy.
* When we built hash tables, we used strdup to make a copy of the key/value,
  but when we built lists, we just copied the pointer.  Why?
  * Intent of the designer
* When should we free memory?
  * When you know that you are done with it

What did we do on Wednesday?
* Stacks
* Queues
* Generalized Linear Collections
* Other policies
* Implemented array-based queues

0. Copy the stuff from Examples/Linear (use the tar file if you'd like)

1. Read the collection-expt.c and figure out what you expect the output
   to be.

2. Compile and run to verify.

3. The output will be borken.  Why?  Fix!

4. The recommended_capacity is ignored.  Stop ignoring it.

5. In the test, I regularly write

  EXPERIMENT (result = collection_get (stuff));
  PRINT_STR (result);

Why don't I write?

  PRINT_STR (collection_get (stuff));

5. Implement stacks.  (Framework is there.)