Chapter 8: Input and Output

5 Find the Bug exercises from Chapter 8 of Everyday Programming. Every program below is short, does something recognizable, and hides exactly one bug — syntax, runtime, or logical. Read it, predict what it does, then run it and find out.

Worked solutions for this chapter: Chapter 8 solutions. Every snippet is also available as a .py file — see Exercises & Solutions.

Exercises 8.1.1–8.1.5

Exercise 8.1.1 — Doubling a recipe

This program asks how many cookies a recipe makes, then prints double that amount.

# Assume the user types: 12
cookies = input("How many cookies does the recipe make? ")
print(f"Doubled, that is {cookies * 2} cookies.")

Solution 8.1.1 · ex_8_1_1.py

Exercise 8.1.2 — Average of two test scores

Assuming the user types 80 then 90, this program should print Your average is 85.0..

# Assume the user types: 80  then  90
score1 = float(input("First test score? "))
score2 = float(input("Second test score? "))
average = score1 + score2 / 2
print(f"Your average is {average}.")

Solution 8.1.2 · ex_8_1_2.py

Exercise 8.1.3 — Printing a shopping list

This program should print three fruits on one line, separated by commas, like apple, banana, cherry.

fruits = ["apple", "banana", "cherry"]
print(fruits[0], fruits[1], fruits[2], sep=" ")

Solution 8.1.3 · ex_8_1_3.py

Exercise 8.1.4 — Saving a temperature reading

This program writes one weather reading to a file and then prints it back.

with open("reading.txt", "w", encoding="utf-8") as f:
    f.write("Tokyo,36.5\n")

with open("reading.txt", "w", encoding="utf-8") as f:
    contents = f.read()

print(contents)

Solution 8.1.4 · ex_8_1_4.py

Exercise 8.1.5 — Greeting by name

This program asks for a name and prints a greeting.

# Assume the user types: Ava
name = input("What is your name? ")
print(f"Hello, {name}! Welcome aboard.)

Solution 8.1.5 · ex_8_1_5.py