Lab Exercise 1

An Introduction to Python Tools

CS 1510
Introduction to Computing

Introduction

Our laboratory sessions are held in 112 Wright. For outside programming assignments, you may also use the computers in 339 Wright and 335 ITTC. These are the only computer labs on campus with the software development tools used in this course. The computers in these labs run both the Windows 7 and Linux operating systems. We will be using Windows 7 in this class.

To login in all these computers, you will use your CatID, the username and passphrase assigned to you by Information Technology Services (ITS).

Log On

Locate a free computer, if you are not already at one.

1. If the machine is booted Linux, reboot the machine into Windows.
2. Press Alt-Ctrl-Del at the same time.
3. You will see instructions about how to log on using your CatID. If you are uncertain about this process than you should read this page before pressing the "Ok" button.
4. Log on using your CatID.
5. Wait until the system logs you in. This process may take a few minutes the first time you log on in the lab.

Access the Rest of the Exercise

Now that you are logged on...

1. Launch the web browser of your choice. We recommend Firefox, but Chrome or Internet Explorer should work fine.
2. Navigate to the course website:

   http://www.cs.uni.edu/~wallingf/teaching/cs1510/

3. Click on the Course Materials link at the left.
4. Click on the link for the Week 1 lab.

You will find the rest of today's instructions there.

Create a Directory for This Class

In order to keep your files for this course together, I strongly encourage that you get into the habit of saving your work on an external USB drive.

• Plug in your USB device.


• Open the graphical representation of the computer by selecting Start | Computer or selecting Computer from the desktop.


• Select the icon for your USB device by double-clicking on it.


• Create a directory on the USB device. Call it cs1510 or intro or something else you like. You can do this by right clicking in the empty area and selecting New | Folder and then renaming the folder that is created.


• Navigate into this directory.


• Create a new sub-folder called lab01 or something similar.

Explore Some Class Details

Let's take a quick look at the syllabus...

• Navigate back to the main page for the course, and follow the link at the left to the Syllabus.


• Find answers to the following questions. Record your answers in a text file named responses.txt.
  • What is my office phone number?
  • What percentage of your final grade comes from programming assignments?
  • What percentage grade do you need in order to earn a B in the course?
  • How many days after the due date may you submit an assignment for grading?
  • What is the tentative date of our first exam?

Use the Python Shell

Our first major tool is the Python shell. It is part of an integrated development environment (IDE) called IDLE.

• Launch IDLE by selecting Start | All Programs | Python 3.4 | IDLE (Python GUI). Do the rest of this task in the window that appears. You will type your items at the >>> prompt.


• Enter the following basic expressions one at a time, each followed by return. Think carefully about what you see. If you don't understand the result, ask!

      "hello, world!"
      1
      1 + 2
      1 + 2 * 3
      print("hello, world")
      prin("hello, world")
  



• Enter a few expressions of your own choosing, each one at a time followed by return. What do you expect to see as a result? What is the actual result you see? If you don't understand the result, ask!


• Record at least one thing you learned by doing this part of lab, in the text file you created earlier.

From now on, when I say

Enter the following expressions.

Enter the following expressions one at a time, each followed by return. Think carefully about what you see.

Grow a Program in the Python Shell

Now let's use the Python shell to grow a program.

• Enter the following expressions. If you get an error, be sure that you typed the expression correctly. Observe how later lines build on or use the earlier lines to perform a larger task.

      import math
      math.pi
      r = 4
      2 * math.pi * r
      circumference = 2 * math.pi * r
      circumference
      math.pi * r ** 2
      area = math.pi * (r ** 2)
      area
      input("Enter the radius of the circle: ")
      r_string = input("Enter the radius of the circle: ")
      r_string
      2 * r_string
      int(r_string)
      r = int(r_string)
      r
      print("circumference = ", circumference)
      print("radius = ", r)
  



• Record one thing you learned by doing this in the text file you created earlier.

Edit a Program in IDLE

Our second major tool is the IDLE editor.

• Open a new programming window by selecting File | New File.


• In this window, type the Python program below, comments and blank lines included. If you are short of time, you may copy expressions from your shell window. But it's must better to type them from scratch!

      ## FILE:     circle.py
      ## AUTHOR:   <your name>
      ## DATE:     08/27/2014
      ## COMMENT:  Compute the area and circumference of a circle.
      ##           This code is adapted from Code Listing 1.1 in the text.
  
      import math
  
      r_string = input("Enter the radius of the circle: ")
      r = int(r_string)
  
      circumference = 2 * math.pi * r
      area = math.pi * (r ** 2)
  
      print("circumference = ", circumference)
      print("radius = ", r)    
  



• Save your program by selecting File | Save. Name it circle.py.


• Run your program by selecting Run | Run Module. You can also run your program by pressing the F5 key.

Congratulations! You have run your first Python program.

Finishing Up

Make sure that your responses file and program file are complete and saved. Now, let's submit your files for grading:

• Log in to the CS 1510 section of the department's electronic submission system using your CatID username and password.


• Select CS 1510, Intro to Computing, Wallingford from the drop-down menu and press Continue.


• Select lab01 -- An Introduction to Python Tools from the radio-list menu and press Continue.


• Press Choose File for each of the files to submit. Navigate to the files on your USB drive and select them. When both are selected, press Continue.


• Verify that your files were submitted. You should see something like this:

      Uploading the following files.
  
         circle.py of size 417 bytes
         responses.txt of size 716 bytes
         The files listed above were uploaded.
         You are responsible to make sure that this list is complete.
         You may replace or add file up until the deadline by using this system again...
  

If you need any help, let me know.

Congratulations! You have completed your first computer science lab.