Comp 2673, Spring 2002

April 3, lecture notes



Reading:
   You should have read Chapters 1-7, 10 and 12 in the Unix book.
   For Friday:
      1.  start reviewing Chapters 6-8 in D&D 
      2.  read and start thinking about and designing programming assignment 1
      3.  work on the homework assignment - try all of the problems so you
          can ask questions in class on Friday (especially problem 5)
      4.  Prepare for quiz

The binary number system
   Representing numbers in binary (translating from/to decimal)
   going from binary to octal and hexadecimal
   addition in binary, hex

Permissions in the Unix file system
   You can use chmod a couple of different ways
   You can change them by adding or removing or setting permissions (+, -, =)
     for user (owner), group, other or all (u, g, o, a)
   They can also be set numerically - each of owner, group, other are
     represented by an octal number, one bit for each of rwx.  For example,
     751 represents permissions rwxr-x--x
   Any permutation of permissions is allowed - but not all are reasonable -
     see chapter 5 of the unix book for a discussion of this

Classes - a review
   In class today, we'll review classes by creating a Maze class
   Recall that classes allow for
      collecting data into packages
      packaging functions together with the data they use and modify
      separating interface from implementation
      hiding data from the client
   Important concepts from classes:
       data members, function members
       private/public
       constructors/destructors
       const members, static members, friends, the this pointer
   Highlights from D&D chapters on classes (click on "Chapter Highlights" in
       the left-hand menu):
       Chapter 6

       Chapter 7

       Chapter 8