College Board Big Idea 1

Identifying and Correcting Errors (Unit 1.4)

Become familiar with types of errors and strategies to fixing them

  • Lightly Review Videos and take notes on topics with Blog
  • Complete assigned MCQ questions

Here are some code segments you can practice fixing: 

alphabet = "abcdefghijklmnopqrstuvwxyz"

alphabetList = []

for i in alphabet:
    alphabetList.append(i)

print(alphabetList)

['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']

The intended outcome is to determine where the letter is in the alphabet using a while loop

  • What is a good test case to check the current outcome? Why?
  • Make changes to get the intended outcome.
letter = input("What letter would you like to check?")

i = 1

while i < 26:
    if alphabetList[i] == letter:
        print("The letter " + letter + " is the " + str(i+1) + " letter in the alphabet")
    i += 1

The letter b is the 2 letter in the alphabet

The intended outcome is to determine where the letter is in the alphabet using a for loop

  • What is a good test case to check the current outcome? Why?
  • Make changes to get the intended outcome.
letter = input("What letter would you like to check?")

count = 0
for i in alphabetList:
    if i == letter:
        print("The letter " + letter + " is the " + str(count+1) + " letter in the alphabet")
    count += 1

The letter z is the 26 letter in the alphabet

This code outputs the even numbers from 0 - 10 using a while loop.

  • Analyze this code to determine what can be changed to get the outcome to be odd numbers. (Code block below)
evens = []
i = 0

while i <= 10:
    evens.append(i)
    i += 2

print(evens)    

[0, 2, 4, 6, 8, 10]

This code should output the odd numbers from 0 - 10 using a while loop.

odds = []
i = 1

while i <= 10:
    odds.append(i)
    i += 2

print(odds)

[1, 3, 5, 7, 9]

This code outputs the even numbers from 0 - 10 using a for loop.

  • Analyze this code to determine what can be changed to get the outcome to be odd numbers. (Code block below)
numbers = [0,1,2,3,4,5,6,7,8,9,10]
evens = []

for i in numbers:
    if (numbers[i] % 2 == 0):
        evens.append(numbers[i])

print(evens)

[0, 2, 4, 6, 8, 10]

This code should output the odd numbers from 0 - 10 using a for loop.

numbers = [0,1,2,3,4,5,6,7,8,9,10]
odds = []

for i in numbers:
    if (numbers[i] % 2 != 0):
        odds.append(numbers[i])

print(odds)

[1, 3, 5, 7, 9]

The intended outcome is printing a number between 1 and 100 once, if it is a multiple of 2 or 5

  • What values are outputted incorrectly. Why?
  • Make changes to get the intended outcome.
numbers = []
newNumbers = []
i = 0

while i < 100:
    numbers.append(i)
    i += 1

for i in numbers:
    if numbers[i] % 5 == 0 and numbers[i] != 0:
        newNumbers.append(numbers[i])
    if numbers[i] % 2 == 0 and numbers[i] != 0:
        newNumbers.append(numbers[i])

print(newNumbers) 

[2, 4, 5, 6, 8, 10, 10, 12, 14, 15, 16, 18, 20, 20, 22, 24, 25, 26, 28, 30, 30, 32, 34, 35, 36, 38, 40, 40, 42, 44, 45, 46, 48, 50, 50, 52, 54, 55, 56, 58, 60, 60, 62, 64, 65, 66, 68, 70, 70, 72, 74, 75, 76, 78, 80, 80, 82, 84, 85, 86, 88, 90, 90, 92, 94, 95, 96, 98]

Challenge

This code segment is at a very early stage of implementation.

  • What are some ways to (user) error proof this code?
  • The code should be able to calculate the cost of the meal of the user

Hint:

  • write a “single” test describing an expectation of the program of the program
  • test - input burger, expect output of burger price
  • run the test, which should fail because the program lacks that feature
  • write “just enough” code, the simplest possible, to make the test pass

Then repeat this process until you get program working like you want it to work.

menu =  {"burger": 3.99,
         "fries": 1.99,
         "drink": 0.99}
total = 0

#shows the user the menu and prompts them to select an item
print("Menu")
for k,v in menu.items():
    print(k + "  $" + str(v)) #why does v have "str" in front of it?

#ideally the code should prompt the user multiple times
for t, k in menu.items():
    item = input("Please select an item from the menu")
    if item == "break":
        break
    total = total + menu[item]

print("Total is: $" + str(total))

#code should add the price of the menu items selected by the user

Menu
burger  $3.99
fries  $1.99
drink  $0.99
Total is: $4.98

Hacks Questions

Now is a good time to think about Testing of your teams final project...

  • What errors may arise in your project?
  • What are some test cases that can be used?
  • Make sure to document any bugs you encounter and how you solved the problem.
  • What are “single” tests that you will perform on your project? Or, your part of the project?
    • As Hack Design and Test plan action … Divide these “single” tests into Issues for Scrum Board prior to coding. FYI, related tests could be in same Issue by using markdown checkboxes to separate tests.
  1. Some errors that might arise in our project are:
    • Our notes don't save
    • Only one note saves at a time
    • Storing notes/inputs for a specific user
  2. Some test cases that can be used are testing user input and/or how output is displayed. We can also put in random notes and see if the questions that appear are relevant to the notes. We can also check if the answers are correct to their respective question.
  3. We will document any bugs we encounter on our scrum board and/or slack. We can also put possible solutions on them as well.
  4. Some single tests are putting in a random note on a random subject and checking that the note is saved, and the questions and answers are correct and relevant.