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:

#Create a list of the alphabet

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 = 0

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 b is the 2 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 == 1):
        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 or numbers[i] % 2 == 0:
        newNumbers.append(numbers[i])

print(newNumbers) 

[0, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, 22, 24, 25, 26, 28, 30, 32, 34, 35, 36, 38, 40, 42, 44, 45, 46, 48, 50, 52, 54, 55, 56, 58, 60, 62, 64, 65, 66, 68, 70, 72, 74, 75, 76, 78, 80, 82, 84, 85, 86, 88, 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.

#Define dictionary containing all menu items and their corresponding cost 
#All costs are pre-Covid because no way we're getting prices this low anymore

menu =  {"burger": 13.99,
         "wings": 9.50,
         "fries": 5.50,
         "chips": 1.99,
         "soda": 2.99,
         "cookie": 1.99,
         "salad": 9.99}

#Sets the total cost of cart to 0 dollars
total = 0

#Shows the user all menu items and prompts them to select an item
print("Menu:")
print("-------------------------------")
for k,v in menu.items():
    print(k + "  $" + str(v))


#Defines variable "yn" to be used as the condition in the while loop
yn = "y"

#Check if yes/no or "yn" equals y meaning yes
#if yes, continue or redo the loop
while yn == "y":
    print("------------------------------------")

    #Ask the user which menu item they would like
    item = input("Please select an item from the menu")

    #Display the cost of the desired item
    print("cost of: " + 
          item)
    print("$" + str(menu[item]))

    #Add the cost of the desired menu item to the total bill for the day
    total += menu[item]

    #Ask valued customer once again whether they would like to buy anything else
    yn = input("Would you like to buy anything else? (y/n)")

#Print cost of items without tax
print("Cost of items: " + str(total))

#Print total cost of items including tax
print("Tax: " + str(round(0.0725*total, 2)))

#Prompt user, asking for tip percentage for our amazing employees because they are so great
tip = input("Enter tip amount here: ")

#Make sure there aren't any percent symbols before adding to total
tip = tip.replace('%', '')

#Multiply percentage tip to find how much the stingy customer is tipping
tipval = (float(tip)*.01)*total

#Print how much the tip comes out to be
print("Tip: " + str(round(float(tipval), 2)) + " (" + tip + "%)")

#Print the total cost of the customer's amazing meal and experience
print("Total: " + str(round(1.0725*total, 2) + round(float(tipval), 2)))

Hacks

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.