programming for everybody week 7 quiz answers

Chapter 5

1. What is wrong with this Python loop:

n = 5
while n > 0 :
print(n)
print(‘All done’)
  • This loop will run forever
  • The print(‘All done’) statement should be indented four spaces
  • There should be no colon on the while statement
  • while is not a Python reserved word

2. What does the break statement do?

  • Exits the program
  • Jumps to the “top” of the loop and starts the next iteration
  • Resets the iteration variable to its initial value
  • Exits the currently executing loop

3. What does the continue statement do?

  • Exits the currently executing loop
  • Resets the iteration variable to its initial value
  • Exits the program
  • Jumps to the “top” of the loop and starts the next iteration

4. What does the following Python program print out?

tot = 0
for i in [5, 4, 3, 2, 1] :
tot = tot + 1
print(tot)
  • 10
  • 15
  • 0
  • 5

5. What is the iteration variable in the following Python code:

friends = [‘Joseph’, ‘Glenn’, ‘Sally’]
for friend in friends :
print(‘Happy New Year:’, friend)
print(‘Done!’)
  • friend
  • Sally
  • Glenn
  • Joseph

6. What is a good description of the following bit of Python code?

zork = 0
for thing in [9, 41, 12, 3, 74, 15] :
zork = zork + thing
print(‘After’, zork)
  • Count all of the elements in a list
  • Find the largest item in a list
  • Find the smallest item in a list
  • Sum all the elements of a list

7. What will the following code print out?

smallest_so_far = -1
for the_num in [9, 41, 12, 3, 74, 15] :
if the_num < smallest_so_far :
smallest_so_far = the_num
print(smallest_so_far)

Hint: This is a trick question and most would say this code has a bug - so read carefully

  • -1
  • 74
  • 42
  • 3

8. What is a good statement to describe the is operator as used in the following if statement:

if smallest is None :
smallest = value
  • Is true if the smallest variable has a value of -1
  • matches both type and value
  • Looks up ‘None’ in the smallest variable if it is a string
  • The if statement is a syntax error

9. Which reserved word indicates the start of an "indefinite" loop in Python?

  • break
  • while
  • indef
  • def
  • for

10. How many times will the body of the following loop be executed?

n = 0
while n > 0 :
print(‘Lather’)
print(‘Rinse’)
print(‘Dry off!’)
  • 0
  • 1
  • This is an infinite loop
  • 5

Assignment 5.2

5.2 Write a program that repeatedly prompts a user for integer numbers until the user enters 'done'. Once 'done' is entered, print out the largest and smallest of the numbers. If the user enters anything other than a valid number catch it with a try/except and put out an appropriate message and ignore the number. Enter 7, 2, bob, 10, and 4 and match the output below.

largest = None
smallest = None

while True:
user_input = input(“Enter an integer number (or ‘done’ to exit): “)

if user_input == ‘done’:
break

try:
number = int(user_input)

if largest is None or number > largest:
largest = number

if smallest is None or number < smallest:
smallest = number

except ValueError:
print(“Invalid input”)

if largest is not None and smallest is not None:
print(“Maximum is”, largest)
print(“Minimum is”, smallest)
else:
print(“No valid numbers entered.”)

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