• Due
• What You Need to Do
• Setup On Your Machine
• Specification
• Output
• Suggestions
• Testing on Your Machine
• Copy the Script to Unix
• Testing the Script on Unix (Optional)

Due

Sunday, September 28th at 11:59 PM

What You Need to Do

• Create the script hw4.py
• Make sure it obeys the rules in Rules for Homework Scripts
• Move it to an an hw4 directory on pe15.cs.umb.edu

Setup On Your Machine

• Open a text editor.
  I would suggest the text editor built into the program IDLE.
• Save the file as hw4.py

Specification

• Light is electromagnetic radiation
• It has a frequency and a wavelength
• The different colors we see are light of a certain wavelength
• We can only see light of a specific range of wavelengths
• Write a script that will take the wavelength of light in nanometers and turns it into a color
• The color for different wavelengths is given by the following table

Output

• The output should look something like this

  Wavelength: 500
  Green

• The text in blue is what the user enters

Suggestions

• Write this script in stages
• Test your script at each step
• Print the steps below
• And check them off as you finish each one

1. Write an assignment statement which asks the user for a wavelength and stores it in the variable wavelen.
   Convert the value of wavelen using int().
   Print the value of wavelen .
   Save the file and quit.
   Run the script to make sure it works properly.
   If it does not work, fix the problem.
2. Remove the print statement you wrote in the previous step.
   Replace it with an if statement that will run if the value of wavelen is more than 750.
   Inside the if write an assignment statement that gives color the value "No color".
   Outside this statement, print the value of color.
   Run the script.
   Fix any errors you find.
3. Underneath the if statement but before the print statement, write and elif clause that runs if the value of wavelen is greater than or equal to 610.
   Inside the elif clause write an assignment statement that gives color the value "Red".
   Run the script.
   Fix any errors you find.
4. Repeat the steps above for the remaining colors.
5. After the last elif clause, write an assignment statement that gives color the value "No color".
   Run the script.
   Fix any errors you find.

Testing on Your Machine

• Open IDLE
• Use the Open command in IDLE to open hw4.py
• Run your script inside IDLE
• Your output should look something like this

  Wavelength: 510
  Green

• The text in blue is what you enter at the command line
• You should test your script with the following values to make sure your script works for all colors

  751
  750
  621
  620
  591
  590
  571
  496
  495
  451
  450
  381
  320

Copy the Script to Unix

• Open FileZilla and connect to pe15.cs.umb.edu
• Go to your it116 directory
• Go to your hw directory
• Right-click in the whitespace inside the hw directory
• Enter hw4 in the dialog box
• Click and drag your script from the bottom left panel to the bottom right panel
• Right-click on the file and select "Permissions" from the menu

Testing the Script on Unix (Optional)

• Connect to pe15.cs.umb.edu using an ssh client like putty.exe (Windows) or ssh (Mac)
• Go to the directory for this exercise

  cd  it116/hw/hw4

• Run this script

  python3 hw4.py

• You should see something like this

  Wavelength: 
  Green

• The text in blue is what you enter at the command line

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