CMSC 202 Computer Science II, Spring 2007, Section 010x

Lecture 13: Genericity

Tuesday 03/13, 2007

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Assigned Reading:   

Slides As Shown:

• Announcements, etc: [slide view] [print view]

• Destructors, Constructors and Assignment : [slide view] [print view]

• Genericity : [slide view] [print view]

Topics Covered:

• Reminder: Midterm exam is next Thursday, March 15. Please bring a photo ID unless you know that I know that you know that I know who you are.

• Went over list of topics that are fair game for Exam I. (See announcement slides.) Reviewed some topics from students' questions.

• Followed up question from last time: Can you invoke an objects destructor explicitly?

  Answer: Yes, but you dont' want to. See C++ FAQ Lite for a complete disucssion. Basically, you end up freeing the same memory twice, because the object's destructor will be called again, when the object goes out of scope. This is not good. Here are two programs demonstrating bad behavior: bad6.cpp, bad7.cpp.

  The C++ FAQ mentions one situation where explict invocation of an object's destructor makes sense. This situation involves placment new which we will not discuss.

• Finished discussion of copy constructors and the overloaded assignment operator. See slides linked above.

  • New version of DMC with copy constructor and assignment operator dmc2.h, dmc2.cpp.

  • Check that assignment and copy constructors work: good1.cpp.

  • DMC object as a data member of AClass: good2.cpp.

  • Passing a DMC object by value and returning by value: good3.cpp

• Discussed how to use void * pointers and function pointers to achieve genericty in C. See slides.

  • Some code demonstrating the use function pointers: fptr1.c , fptr2.c , fptr3.c , fptr4.c .

  • Code that implements a generic Selection Sort algorithm. genselect.h, genselect.c, genmain1.c, genmain2.c.