Announcements

• Welcome to CS21

Introduction

Welcome to CS21! This course will introduce fundamental ideas in computer science while also teaching you how to write computer programs. We will study algorithms for solving problems and implement solutions in the Python programming language. Python is an interpreted language that is known for its ease of use. We also introduce object-oriented programming and data structures. A deeper coverage of these topics will be presented in CS35.

This course is appropriate for all students who want to learn how to write computer programs and think like computer scientists. It is the usual first course for computer science majors and minors. Students with advanced placement credit or extensive programming experience should place out of this course and instead begin with CS35. If you have no prior computer science or programming experience, this course is designed for you.

Goals for the Course

By the end of the course, we hope that you will have developed the following skills:

• Given a program, be able to simulate on paper how a computer would execute the program, and show the results that would be produced.
• Given a problem, be able to design a clear, concise, and correct pseudo code algorithm to solve it.
• Given a pseudo code algorithm, be able to successfully implement it in Python.
• Be able to use top-down design to sub-divide a large problem into reasonably-sized modular sub-problems.
• Given several algorithms for solving the same problem, be able to analyze which algorithm would be more efficient in terms of running time.
• Develop debugging and unit testing skills. Consistently use these skills while implementing programs.
• Learn to work as part of a team to solve problems starting from design and continuing through to implementation.

Class info

Room: Science Center 240
Time: MWF 10:30–11:20am
Text: Python Programming: an Introduction to Computer Science by John Zelle

Instructional staff

Professor: Richard Wicentowski
Office: Science Center 251
Phone: (610) 690-5643
Office hours: by appointment

Student Support: Betsy Horner
Office: Science Center 255
Email: bhorner1
Phone: (610) 957-6062

Student Mentors: Maria Kelly, Ashley Oudenne
Other Section: Andrew Danner (TR 9:55–11:10am)

Study sessions

Several student mentors will assist me in class and run study sessions in the main CS lab (Science Center 240) on the following evenings:

Day	Time	Location
Sunday	7:00–9:00pm	Sci Center 240
Wednesday	7:00–9:00pm	Sci Center 240

You are invited – and encouraged – to participate in these study sessions to prepare for quizzes, to discuss programming concepts, and to get friendly assistance in working on homework assignments. Our CS mentoring team is dedicated to helping students, who have no prior knowledge of computer science, learn to program in Python while keeping their senses of humor intact. As an added bonus, free food will be provided at the sessions.

Weekly Lab Sessions

The CS lab is open 24 hours a day, 7 days a week for you to use for CS21 lab assignments. In addition, the CS21 professors will be in the main CS labs to help CS21 students with their lab assignements. You are not required to attend any of these sessions, but you should take advantage of them to get assistance with your lab assignments. Any CS21 student is welcome to attend any session.

Time	Professor	Location
Monday 2:00–3:30pm	Wicentowski	Science Center 240
Monday 3:00–4:30pm	Danner	Science Center 240

Schedule

WEEK	DAY	ANNOUNCEMENTS	TOPIC & READING	LABS
1	Jan 19		Introduction to Python and Unix Chapt. 1-2	Lab 0 Lab 1
	Jan 21	Using Unix: 7:30 pm Sci240 (Jan 21) Using Unix: 8:15 pm Sci240 (Jan 22)
	Jan 23
2	Jan 26		Numbers and Strings Chapt. 3-4 (Skip 4.6)	Lab 2
	Jan 28	ASCII table
	Jan 30	Drop/Add ends Practice Quiz 1 Quiz 1
3	Feb 02		Booleans Chapt. 7	Lab 3
	Feb 04
	Feb 06
4	Feb 09		Graphics, objects Chapt. 5	Lab 4
	Feb 11
	Feb 13	Practice Quiz 2 Quiz 2
5	Feb 16		Functions, objects Chapt. 6	Lab 5
	Feb 18
	Feb 20
6	Feb 23		Loops, Top Down Design Chapt. 8, 9	Lab 6
	Feb 25
	Feb 27	Practice Quiz 3 Quiz 3
7	Mar 02		Top Down Design, Loops Chapt. 8, 9	Lab 7
	Mar 04
	Mar 06
	Mar 09	Spring Break
	Mar 11
	Mar 13
8	Mar 16		Searching, Analysis of Algorithms Chapt. 13.1	Lab 8
	Mar 18
	Mar 20
9	Mar 23	Practice Quiz 4 Quiz 4 (Double Quiz)	Recursion, Sorting Chapt. 13.2-13.3	Lab 9
	Mar 25
	Mar 27
10	Mar 30		More Recursion, More Sorting Chapt. 11.6	Lab 10
	Apr 01
	Apr 03	Practice Quiz 5 Quiz 5
11	Apr 06		Dictionaries	Lab 11
	Apr 08
	Apr 10
12	Apr 13		Defining new classes Chapt. 10	Lab 12
	Apr 15
	Apr 17	Practice Quiz 6 Quiz 6
13	Apr 20		Object Oriented Design Chapt. 12	Lab 13
	Apr 22
	Apr 24
14	Apr 27		Linked lists Handout on Blackboard	Lab 14 (optional)
	Apr 29
	May 01	Practice Quiz 7 Quiz 7
	May 15	Final Exam: Friday, May 15 from 7 - 10pm

Grading

Grades will be weighted as follows:

40%	Homework assignments
30%	Quizzes
5%	Class Participation
25%	Final Exam

Homework policy

Programming assignments will typically be assigned in class at the beginning of the week and will be due before midnight the following Tuesday night. You are strongly encouraged to start early and to attend the study sessions for extra practice.

You will submit you assignments electronically using the handin21 program. You may submit your assignment multiple times, but each submission overwrites the previous one and only the final submission will be graded. Late assignments will not be accepted except in extreme situations and only if you contact me before the deadline. Even if you do not fully complete an assignment, you may submit what you have done to receive partial credit.

How to Succeed in CS21

• Read the material before you come to class.
  Don't worry about total comprehension, but at least get a feel for what we will be covering that week. If you have some understanding of the material coming into class, it will be easier for you to ask questions during class, rather than later when help may not be available. Additionally, we often do lab exercises during class. This is an important part of the learning process, as these exercises give you immediate experience with the material we are covering. If you read the book before you come to class, you'll be able to complete these exercises more easily.
• Ask questions if you don't understand.
  This means both during class and while doing your homework. This class continually builds on previous material, so if you don't understand something one week, it will continue to be a problem the next week, and the week after that, and so on. If you need help, ask your classmates, attend the study sessions, come talk with me during my office hours, or email me your question.
• Start the homework assignments early.
  I realize this one is not always easy to do, but if you can get in the habit of doing this, you will be much better off. If you get stuck early (i.e., not two hours before it is due), there will be time to look for help. In addition, if you start early enough, you can take a break, go do something else, and come back later. I find I always have at least a few new ideas when I come back to a problem after a break. If you wait until the last minute, you can't do this.
• Practice, practice, practice.
  The only effective way to learn the material and pass the quizes and exams is to consistently do the homework. Finish all of the assigned programs (and do some extras, for fun!). Even if you don't get them done on time, they will still help you learn the material.
• Seek help early and often.
  Because course material builds on previous material, it is essential to your success in this class that you keep up with the course material. If you are having difficulty with a programming assignment, if you didn't follow something covered in lecture, if you feel you need some extra help understanding or practicing some of the course material, or if you just want to discuss something from a lecture, an assignment, or the text, please come to my office hours.
• Attend CS21 Study Sessions.
  The CS21 Student Mentors (Ninjas) hold evening study sessions each week. You are encouraged to participate in these sessions. The Ninjas will help you prepare for quizzes, will provide additional instruction in programming concepts, and will provide friendly assistance on your homework assignments.
• Work with a partner.
  Several of the assigments will optionally allow you to work with a partner. This is highly recommended: working with a partner can help you progress through the assignment more quickly; partners can often catch silly coding mistakes that may leave you frustrated for hours if working alone; and, explaining concepts and ideas to a partner is a great way to help you learn the material and clarify your thinking. If you are interested in working with a partner but do not know who to ask, contact me and I can try to pair you up with a compatible student.

Programming Style

Programming is not a dry mechanical process, but a form of art. Well written code has an aesthetic appeal while poor form can make other programmers and instructors cringe. Programming assignments will be graded based on style and correctness. Good programming practices usually include many of the following principles:

• A comment at the top of the program that includes:
  • Program authors
  • Date or Dates
  • A brief description of what the program does
• Concise comments that summarize major sections of your code
• Meaningful variable and function names
• Function comments that include:
  • description of what function does
  • description of input parameters
  • description of return value or values
• Well organized code
• White space or comments to improve legibility
• Avoidance of lines longer than 80 characters (the default width of the xemacs window)
• Avoidance of large blocks of copy-pasted code

Also, look over the Python Code Style Guide for more details and some example of good style.

Academic Integrity

Academic honesty is required in all work you submit to be graded. You may not submit work done with (or by) someone else. You may not examine or use work done by others to complete your own work. You may discuss assignment specifications and requirements with others in the class to be sure you understand the problem. In addition, you are allowed to work with others to help learn the course material. However, with the exception of the student mentors and your partner on group assignments, you may not work with others on your assignments.

All code you submit must be your own with the following permissible exceptions: code distributed in class, code found in the course text book, and code worked on with an partner. In these cases, you should always include detailed comments that indicates on which parts of the assignment you received help, and what your sources were.

"It is the opinion of the faculty that for an intentional first offense, failure in the course is normally appropriate. Suspension for a semester or deprivation of the degree in that year may also be appropriate when warranted by the seriousness of the offense." - Swarthmore College Bulletin (2008-2009, Section 7.1.2)

Please see me if there are any questions about what is permissible.

External Links

Links that are related to the course may be posted here. If you have suggestions for links, let me know.

Python style guide From Prof. Tia Newhall
Using Unix Improved
Basic Unix Commands
Python Documentation
Textbook site
How To Think Like a Computer Scientist: Learning with Python