CS 115 Summer 2017,

Lab 1 :

Due in Tuesday 6/13/17 in Lab

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Educational goals of this lab - verify that every student can

• use the Python IDE to create and run a program in Python
• find and fix a syntax error and a semantics (logic) error
• submit a file for grading using the provided submit link

INSTRUCTIONS:

• Problem: Getting a program to run
  • On your machine or a lab machine, run your choice of Python IDE (IDLE or WingIDE or other).
  • Copy and paste the Python program below into the IDE editor. The program is everything between the two horizontal lines on the page.
  • Try executing it with the Run button. It crashes!
  • There are TWO errors in this program. You need to find them, fix them and submit the fixed program.

    ---

    
    

    ---

    # Prolog
    # Author:  Mary Smith
    # Email:  Mary.Smith@uky.edu
    # Section: 00
    # Date: 8/31/15
    '''
      Purpose: to find the area and diagonal length of a rectangle, given the length
        and the width of the rectangle
      Preconditions: (inputs)
        User supplies the length and the width of the rectangle as numbers
      Postconditions: (outputs)
        User greeted and prompted for input of the two dimensions
        Rectangle area and diagonal length displayed
    
    '''
    from math import sqrt # used for Pythagorean theorem
    
    def main():
    # Design and implementation
    
    #  1.  Output a message to identify the program
       print("Area and Length of Diagonal of a Rectangle")
    
    #  2.  Input length and width of the  rectangle from user
       length = float(input("Enter length of rectangle: "))
       width = float(input("Enter width of rectangle: ")
    
    #  3.  Calculate the area of the rectangle using product of length and width
       area = length + width
    
    #  4.  Calculate the length of the diagonal of the rectangle using Pythagorean theorem
    #      to find the length of the hypotenuse (the diagonal)
       diagonal = sqrt(length **2 + width **2)
       
    #  5. Output resulting area and length of diagonal
       print()
       print("The area of a rectangle with length", length, "and width", width)
       print("is", area)
       print("The length of the diagonal of a rectangle with length", length, "and width", width)
       print("is", diagonal)
    
    main()
    # end of program file
    

    ---

  • Test Cases

    Here are two test cases for the program (IF it were correct). Your program MUST produce the output of both of these cases correctly. When you have the program running correctly, make sure your TA or the lecturer in the class see that you can run them.
    Test Case 1:

    Area and Length of Diagonal of a Rectangle
    Enter length of rectangle: 3
    Enter width of rectangle: 4
    
    The area of a rectangle with length 3.0 and width 4.0
    is 12.0
    The length of the diagonal of a rectangle with length 3.0 and width 4.0
    is 5.0
    

    
    Test Case 2:

    Area and Length of Diagonal of a Rectangle
    Enter length of rectangle: 1000
    Enter width of rectangle: 2000
    
    The area of a rectangle with length 1000.0 and width 2000.0
    is 2000000.0
    The length of the diagonal of a rectangle with length 1000.0 and width 2000.0
    is 2236.06797749979
    

  • Document the errors and fixes

    Create a text file (either IDE's editor will create one, or you can use Notepad). You should put into the file (named errors.txt) a description of the two errors you found.

    1. State what the syntax error was.
    2. Copy and paste into the text file the error message you got for the syntax error.
    3. State what the semantics (logic) error was.
    4. State what line the semantics error was on in the program. Hint for IDLE: IDLE's editor does tell you what line number the cursor is in, just look in the lower right corner of the edit window.
    5. State how you fixed the semantics (logic) error.
    6. Save the file and name it errors.txt.
  • Update the prolog

    Notice the personal information in the comments (#) at the top of the program. This is called the program prolog or header comment. You are required to provide a prolog like this for program assignments. Providing a prolog will be part of the grade for the program. Change this prolog to match your information.

  • Save the program file as rectangle.py. After you fix the two bugs, it should run without errors and produce the correct output given above.

  • When you are done, zip the two files(rectangle.py) and the text file (errors.txt) and submit the zip file as a submission for Lab 1 on CANVAS.
    

    This must be done by end of your lab period. Notice that if your program has syntax errors, an error message would appear between the two horizontal bars. For this submission there should be no error message. If you do get an error message, fix the error and submit again.

Why do we ask you to do this? A good part of this class involves writing Python programs, running them, testing them, fixing them. You need to start learning how you use the tools of the trade to do this. You will definitely run into many different errors when you are writing programs; every programmer does. You need to start gaining experience in what the error messages mean and how you can fix them.