Class 01: Introduction

Held Monday, January 25

Summary

• Course overview
• Introduction to data structures and algorithms
• Introduction to programming paradigms
• Assignment: Introductory survey Due before class on Tuesday!

Contents

About this class

• CS152 is primarily a course in Data Structures and Algorithms. At some institutions, it has that name.
  • A data structure is a formalism for organizing and managing data. Often, the way you organize the information in your program permits or inhibits particular operations. Different structures may also lead to different costs (in time or space).
  • An algorithm expresses the steps involved in completing a task.
• CS152 is also a course in procedural and object-oriented programming.
  • Presumably, you've seen a little bit of each in CS151 (or whatever course you've taken previously). We will certainly talk more about both paradigms.
  • We will be doing our programming in Java. However, the language we use is less important than the concepts we learn.
• Like most computer science courses, CS152 will have both theoretical and practical components. I hope you will enjoy relating the two.

Grounding ourselves

• Before we delve too far into these issues, we should ground ourselves somewhat by asking ourselves a few questions (and I'll be asking these of the class).
  • What is Computer Science?
  • What is Computer Programming?
  • How are they similar? How are they different?
  • What is an algorithm?
  • What is a computer program?
• We also want to ask ourselves some practical questions.
  • What programming languages do we know?
  • What CS or programming concepts are we least comfortable with?
  • How comfortable are we with the workstations and Unix?
• Finally, I'd like you to reflect on the course (and you'll be doing this again on the introductory survey).
  • Why are you taking this course?
  • What do you expect to get out of this class?

Administrative Issues

• Please refer to the course web site.

An introduction to data structures

• A data structure is a structure designed to organize data. Those of you coming from the Scheme-based 151 may already be familiar with two basic data structures: the list and the vector.
• Both lists and vectors gather data into a sequence.
• More importantly, they provide facilities for manipulating the sequence.
  • You can extract an element from the sequence.
  • You can change an element in the sequence.
  • (Sometimes) you can insert or remove an element from the sequence.
• Vectors and lists differ in the operations they provide and the costs associated with each operation.
• In designing your own data structures, you will be concerned with
  • The specification -- the description of the data structure and the operations it provides.
  • The implementation -- how you actually provide those operations (and how you store the data to provide those operations).
  • The efficiency of your implementation -- how much it costs to provide those operations.
  • The applications of the data structure.
• (Note that we want a clear barrier between specification and implementation, so that a client of one of your data structures need only know what you do and not how you do it.)
• This term, we will be looking at each of these aspects of a number of the key data structures in CS.

The programming paradigms

• Computer Scientists have developed a number of strategies for looking at algorithm and data design, including
  • procedural / imperative
  • object-oriented
  • functional
  • logical
  • declarative
• While individual definitions of each category may differ, most definitions have some similarities.
• In CS151, you studied functional and imperative programming.
• In CS152, you will study object-oriented and imperative programming.

History

• Created Monday, January 11, 1999
• Filled in the details on Monday, January 18, 1999, based primarily on materials that I had written for a prior session of CS152.
• Cleaned up the contents a little on Monday, January 25, 1999.
• Removed the section on object-oriented programing on Tuesday, January 26, 1999.