UMBC CMSC202, Computer Science II, Spring 1998, Sections 0101, 0102, 0103, 0104 and Honors

Tuesday March 17, 1998

Assigned Reading:

• A Book on C:
• Programming Abstractions in C:

Handouts (available on-line): none.

Topics Covered:

• Finished discussion on the linked list implementation of the simple list ADT from last week. (See header file, implementation, main program and sample run.) A few bugs were found in the original implementation. There were memory leaks in the Delete() and Concatenate() functions. Also, the Delete() function did not check if the last node of the linked list was being deleted. The source code in the web pages have these problems fixed now.

• Impromptu discussion about the advantages and disadvantages of having the system do garbage collection (used by LISP and Java) versus having the programmer explicitly free memory that is no longer needed (used by C and C++).

• We substituted an array implementation of the list ADT for the linked list implementation. We used a new name "list1a.h" for the new header file to avoid confusion, but as far as the main program is concerned it could have been called "list1.h". Note that the main program worked just fine without modification because all uses of the list ADT is through the functions defined by the header file. (See sample run.)

• Compared and contrasted the performance of the array implementation versus the linked list implementation of the list ADT.

• Discussed topics for Exam 2.