COMP 171: Principles of Computer Science I John Barr

What is Computer Science? Problem Solving  Understanding the problem/challenge  Breaking down the problem into solvable pieces  Using the tools you have to solve the problem

What is Computer Science? Solution: An Algorithm  Step-by-step procedure to solve the problem from beginning (start state) to end (end state)

What is Computer Science? For CS, algorithms need to be expressed in a form the computer can understand. Programming Language  Your way to tell the computer your algorithm (your solution)  Computer will only do what you tell it to do

Our Programming Language: Python - Version 3.x Powerful, but easy to use Interpreted Language (not compiled)  Simple syntax  Runs immediately (but slightly slower) Allows for Rapid Prototyping

Our Course Learn to solve problems with computers by creating algorithms, and translating those algorithms in Python code. Give the computer instructions to solve instances of the problem for us.

Typical Weekly Schedule MTUWTHFSASU New TopicNew Lab Deeper into new topic Extra challenge Working on labReading / Working on Homework Homework Due Lab due Quiz Our Course

Sakai for Class Information Syllabus Textbook Assignments TA hours Class web site Other resources Start Python download now…  Python 3.x

Our Book / Homework System Interactive Python, by Runestone Interactive  Google “Interactive Python”  To create an account, scroll to the very bottom of this page, and click the small blue "register" link.  The course name is: IC-Comp-17-FA-14 After, submit your username on Sakai

Starting with Python - IDLE The environment we will use to create and run python programs Very simple Downloads with python

IDLE: Using the shell >>> >>> print "Hello, World" Hello, World Tinkering in the shell is fine, but when you want to maintain / save / share your work, use a module.

Creating a module print “Running Module” def main(): #comment inside module print ("Hello, World”) main() Select “Run > Run Module” (save the file as “HelloWorld”) A shell will open up with your program loaded In IDLE: Select “File -> New Window” or “File->New File” on a Mac This new window is a “module” Type the following: