CS Computing Lab 1 Solved

Overview

In this lab, we will install the software we will need to write and run Python programs, gain familiarity with basic command line tools, and write and run our rst Python program.

This lab provides detailed instructions for Windows 10 and MacOS 10.9 or higher.

    • Activity: Install Python

If your operating system is Windows, complete Section 1.2. If you have an Apple computer, complete Section 1.1.

1.1    macOS

Download Python installer If your macOS version is in the range 10.6-10.8, use the following link to download the Python installer:

Use this link to download the installer:

https://www.python.org/ftp/python/3.7.4/python-3.7.4-macosx10.9.pkg

Install Python  Double click on the installer to run it (should be called python-3.7.4-macosx10.9.pkg).

Follow the directions on the installer screens to install Python.

    • On the screen titled \Welcome to the Python Installer", click \Continue".

    • On the next screen, titled \Important Information", click \Continue".

    • On the next screen, titled \Software License Agreement", click \Continue" and then \Agree" on the window that pops up.

    • Then select the hard drive onto which you wish to install Python. In most cases, you should only have one option. Then click \Continue".

    • Finally, you will then see a screen with title \Standard Install on Macintosh HD", click \Install". There is no need to customize the installation or change the install location.



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1.2    Windows

Check Windows version First, check whether you have 32-bit or 64-bit Windows installed. Do this by going to the \Start" menu in the bottom left, then click \Settings", then \System". In the menu on the left side of the window, click \About". Whether the operating system is 32 or 64-bit will be shown under the heading \Device speci cations". See Figure 1.2 for an example.





















Figure 1: Displaying the Windows version



Download Python installer If you have a 32-bit version of Windows installed, use the following link to download the Python installer:

https://www.python.org/ftp/python/3.7.4/python-3.7.4.exe

If you have the 64-bit version of Windows, use this link:

https://www.python.org/ftp/python/3.7.4/python-3.7.4-amd64.exe

Install Python Next, double click on the downloaded installer le (should be python-3.7.4.exe if 32-bit or python-3.7.4-amd64.exe if 64-bit). You will then see a screen like the one in Figure 1.2.


















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Figure 2: Windows installation screen



IMPORTANT On this screen, make sure you check the box \Add Python 3.7 to PATH" marked in red in Figure 1.2. AFTER YOU HAVE CHECKED THIS BOX, complete the installation by clicking on the \Install Now" option marked in black in Figure 1.2. This will be important both for running programs from the command line (see below for more on this) and installing additional Python packages (later in the course).

1.3    Other operating systems

To install Python for other operating systems, use a package manager (e.g., apt for Debian or Ubuntu, yum for Red Hat or Fedora, dnf for Fedora).

If you have no package manager or wish to compile from source, you can download source les from here:

https://www.python.org/downloads/release/python-374/

    • Activity: Install Atom

2.1    macOS

You can download Atom using this link:

https://github.com/atom/atom/releases/download/v1.40.1/atom-mac.zip

The downloaded le atom-mac.zip will either be automatically unzipped or you can double click on it to unzip. Inside, will be a le called Atom or Atom.app. You may move this le to wherever you would like to put it (e.g., your Applications folder). Then double click on it to open it.

2.2    Windows

Download Atom installer If you a 32-bit version of Windows, download the Atom installer using this link:

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https://github.com/atom/atom/releases/download/v1.40.1/AtomSetup.exe

If you have a 64-bit version, use this link to download the installer:

https://github.com/atom/atom/releases/download/v1.40.1/AtomSetup-x64.exe

Double click on the downloaded installer le (AtomSetup.exe for 32-bit or AtomSetup-x64.exe for 64-bit). Atom will be installed and then open automatically.

2.3    Other operating systems

Atom may be available on package management systems. Also, see the webpage below for additional installation options:

https://github.com/atom/atom/releases/tag/v1.40.1

    • Activity: Write a  rst program

Open Atom. Click the \File" menu in the upper left corner. Then select the \New File" option.

You can close the \Welcome" and \Telemetry Consent" tabs.

In this le, write a program that uses the print function described in lecture to print \Hello, world!".

Make a new folder with the name CS0011. Save the    le as lab1.py.

    • Activity: Use the command line

4.1    Paths

Paths specify locations of    les and directories in the    le system.

macOS  In macOS, paths look like this:

/mydirectory/mysubdirectory/mysubsubdirectory/myfile

Directory and    lenames are separated using /.

Windows  In Windows, paths look like this:

C:nmydirectorynmysubdirectorynmysubsubdirectorynmyfile

The drive is named at the front of the path and directory and    lenames are separated using n.









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Absolute and relative paths A lesystems has a root directory containing all other directories and les. Paths like the above give the location of a le based on the root directory and are called absolute paths. On the other hand, relative paths give the location of a le from some other di-rectory. In the above example, if we are in the directory named mysubdirectory, the relative paths

mysubsubdirectory/myfile (macOS)

or

mysubsubdirectorynmyfile (Windows)

give the location of the    le with name myfile.

4.2    Open the shell

Windows Open the Windows Command Prompt. You can do this by typing \command prompt" in the search bar at the bottom of the desktop screen and clicking on the resulting program.

macOS Open the Terminal. You can do this by using Spotlight to search for \terminal" and opening the program that comes up.

4.3    Navigate through the    le system

When working on the command line, you always have a current or working directory. Think about this as the directory in the le system that you are currently looking at.

macOS  In macOS, you can display the path to the current directory using the pwd command.

Try this now. Your terminal should look something like this:

dwitmer-macbook-pro:    dwitmer$ pwd
/Users/dwitmer

From here, you can use the cd command to navigate to the directory containing your program.

The cd command takes a path and changes the current directory accordingly.

dwitmer-macbook-pro: dwitmer$ cd Documents dwitmer-macbook-pro:Documents dwitmer$ pwd /Users/dwitmer/Documents dwitmer-macbook-pro:Documents dwitmer$ cd CS0011 dwitmer-macbook-pro:CS0011 dwitmer$ pwd /Users/dwitmer/Documents/CS0011

You could also have done this in one step using the entire relative path as follows.

dwitmer-macbook-pro:    dwitmer$ cd Documents/CS0011



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dwitmer-macbook-pro:CS0011 dwitmer$ pwd
/Users/dwitmer/Documents/CS0011

Windows  In Windows, you can print the path to the current directory using the cd command.

C:nUsersndwitmer> cd

C:nUsersndwitmer

From here, you can use the chdir command to navigate to the directory containing your pro-gram. The chdir command takes a path and changes the current directory accordingly.

C:nUsersndwitmer> chdir Documents

C:nUsersndwitmernDocuments> chdir CS0011

C:nUsersndwitmernDocumentsnCS0011>

Note that Command Prompt prints the full absolute path. You could also have done this in one step using the entire relative path as follows.

C:nUsersndwitmer> chdir DocumentsnCS0011

C:nUsersndwitmernDocumentsnCS0011>


4.4    List directory contents

macOS  Now, use the ls command to list the contents of the current directory:

dwitmer-macbook-pro:CS0011 dwitmer$ ls


Windows  Use the dir command to list the contents of the current directory:

C:nUsersndwitmernDocumentsnCS0011> dir


4.5    Output the contents of a    le

macOS  Use the more command to display the contents of the lab1.py  le.

dwitmer-macbook-pro:CS0011 dwitmer$ more lab1.py


Windows  Use the more command to display the contents of the lab1.py  le.

C:nUsersndwitmernDocumentsnCS0011> more lab1.py





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4.6    Make a directory

macOS  Next, use mkdir to make a new directory called lab1 as follows:

dwitmer-macbook-pro:CS0011 dwitmer$ mkdir lab1


Windows  Next, use mkdir to make a new directory called lab1 as follows:

C:nUsersndwitmernDocumentsnCS0011> mkdir lab1


4.7    Copy a    le

macOS Use the cp command to make a copy of your lab1.py le called lab1copy.py. Then use ls to see the new le.

dwitmer-macbook-pro:CS0011 dwitmer$ cp lab1.py lab1copy.py dwitmer-macbook-pro:CS0011 dwitmer$ ls

Use more to verify that it is indeed a copy.

Windows Use the copy command to make a copy of your lab1.py le called lab1copy.py. Then use dir to see the new le.

C:nUsersndwitmernDocumentsnCS0011> copy lab1.py lab1copy.py

C:nUsersndwitmernDocumentsnCS0011> dir

Use more to verify that it is indeed a copy.

4.8    Delete a    le

macOS  Use rm to delete the copy and then con rm that it is gone using ls.

dwitmer-macbook-pro:CS0011 dwitmer$ rm lab1copy.py


Windows  Use del to delete the copy and then con rm that it is gone using dir.

C:nUsersndwitmernDocumentsnCS0011> del lab1copy.py


4.9    Move a    le

macOS  Last, move the lab1.py  le to the lab1 directory using mv:




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dwitmer-macbook-pro:CS0011 dwitmer$ mv lab1.py lab1/lab1.py

To con rm that the move was successful, use the ls command. The le should be gone. Then use ls again with the name of the new directory:

dwitmer-macbook-pro:CS0011 dwitmer$ ls lab1

The    le should be there.

Windows  Move the lab1.py  le to the lab1 directory using move:

C:nUsersndwitmernDocumentsnCS0011> move lab1.py lab1nlab1.py

To con rm that the move was successful, use the dir command. The le should be gone. Then use dir again with the name of the new directory.

C:nUsersndwitmernDocumentsnCS0011> dir lab1

The    le should be there.

    • Activity: Run a  rst program

Finally, we can run our program from the command line.

5.1    macOS

Use cd to change your current directory to lab1. Then run the following:

python3 lab1.py

Your program should print \Hello, world!".

Using the command python (rather than python3) runs an older version of Python that comes preinstalled with macOS. We will not use this older version of Python in this class.

5.2    Windows

Use chdir to change your current directory to lab1. Then run the following:

python lab1.py

Your program should print \Hello, world!".








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