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

Lecture 11: Dynamic Memory Allocation

Tuesday 03/06, 2007

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Assigned Reading:   

Slides As Shown:

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

• Hack vs Kludge : [slide view] [print view]

• 2-D Arrays : [slide view] [print view]

Topics Covered:

• Reminder: Midterm exam is next Thursday, March 15.

• Q & A on Project 2.

• Discussed the difference between a hack and a kludge (see slides above). Here are two programs that hack around the restriction that const functions cannot change a data member: ahack1.cpp, ahack2.cpp. This explains why the designers of C++ had to make the "mutable" option available. If they didn't, programmers would find a way around it anyway.

• Continued the discussion of a perhaps more straightforward implementation of a two dimensional array. (See slides.)

  In the first implementation, we used a member function at() to access items in the 2D array. The [] operator also works, but doesn't check bounds: twodim.h, twodim.cpp, tdtest.cpp.

  In the second implementation, we made the [] operator check bounds, but we had to define a small class SmartIntPtr just to check the column number is in bounds: twodim2.h, twodim2.cpp, tdtest2.cpp.