CS21 — Intro to Computer Science

Announcements | Schedule | Grading | Study Sessions | Style | Integrity | Links
Introduction to Computer Science using Python


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 CS 35.

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 CS 35.

Goals for the course

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


Class info

Room: Science Center 240
Time: MWF 9:30am–10:20am
Text: Python Programming: an Introduction to Computer Science by John Zelle

Instructional staff

Professor: Andrew Danner
Office: Science Center 253
Phone: (610) 328-8665
Office hours: Tuesday 9-11am, Wednesday 1:30-2:30pm, or by appointment

Student Mentors: Carey Pietsch, Ethel Reines, Colin Schimmelfing, and Joel Tolliver


1 Sep 03   Introduction
Writing and running programs in Python
Zelle Chapters 1-2
HW #1
Sep 05  
Sep 07  
2 Sep 10   Computing with numbers and strings
Using pseudocode
Zelle Chapters 3-4
HW #2
Sep 12  
Sep 14 Drop/Add ends
ASCII table
Quiz 1 Practice Quiz
3 Sep 17   Graphics
Graphics and using objects
Zelle Chapter 5
HW #3
Sep 19  
Sep 21  
4 Sep 24   Functions
Zelle Chapter 6
HW #4
Sep 26  
Sep 28 Quiz 2 Practice Quiz
5 Oct 01   Decision structures
Zelle Chapter 7
HW #5
Oct 03  
Oct 05  
6 Oct 08   Loops
Zelle Chapter 8
Oct 10  
Oct 12 Quiz 3 (longer) Practice Quiz

Oct 15


Oct 17

Oct 19

7 Oct 22   Top-down design
Zelle Chapter 9
HW #6
Oct 24  
Oct 26  
8 Oct 29   Recursion
Zelle 13.1-13.3
HW #7
Oct 31  
Nov 02 Quiz 4 Practice Quiz
9 Nov 05   Dictionaries
Zelle Chapter 11 (pgs 367-375)
HW #8
Nov 07  
Nov 09 Last day to declare CR/NC or
Withdraw with a "W"
10 Nov 12   Defining new classes
Zelle Chapter 10
HW #9
Nov 14  
Nov 16 Quiz 5 Practice Quiz
11 Nov 19   Object-oriented design
Zelle Chapter 12
Nov 21  

Nov 23

Thanksgiving Break

12 Nov 26   Linked lists HW #10
Nov 28  
Nov 30 Quiz 6 Practice Quiz
13 Dec 03   Binary search trees HW #11
Dec 05  
Dec 07  
14 Dec 10   Review  

Dec 16

Final Exam (A) 2pm SCI 181


Dec 18

Final Exam (B) 9am SCI 181


Grades will be weighted as follows:
35%Homework assignments
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.

Study sessions

Several student mentors will assist me in class and run study sessions in the robot lab (Science Center 252) on Sundays and Wednesdays from 7-9pm.

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.

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:

Academic Integrity

Academic honesty is required in all work you submit to be graded. With the exception of your lab partner on lab assignments, you may not submit work done with (or by) someone else, or 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 your lab partner, you may not work with others on your assignments in any capacity.

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 assigned partner. In these cases, you should always include detailed comments that indicates which parts of the assignment you received help on, 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 (2007-2008, Section 7.1.2)

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

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

Using Unix Improved
Python Documentation
Textbook site
How To Think Like a Computer Scientist: Learning with Python
Python for Java Programmers