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.”)
