CS 2 - Python Unit 1

What’s wrong with this code?

def go():

move()

move()

def go():

move()

move()

move()

go()

go()

• The go function is called twice

• The go function has been defined twice

• The go function has a syntax error

• go is not a command that Karel understands

What is wrong with this for loop?

for i in range = 5; move()

A. The for loop uses a semicolon(;) instead of colon(:)

B. It should say range(5) instead of range = 5

• The for loop is correct

• A

• B

• A and B

What does the mystery function do?

def mystery():

while no_balls_present():

move()

• Karel moves until it is on a ball

• Karel moves once if there is no ball present

• Karel moves until it puts down a ball

• Karel checks if there is no ball on the current spot and then moves once

Say Karel is on a location with one tennis ball. After the following code runs, how many tennis balls will there be at that location?

for i in range(3):

if balls_present():

take_ball()

else:

put_ball()

put_ball()

• 0

• 1

• 2

• 6

Why does a programmer indent their code?

• Helps show the structure of the code.

• Easier for other people to understand.

• In Python, it is used to help determine what parts of a code are included in a code block, such as an if statement or for loop.

• All of the above

Say you want to write a program to have Karel put down 300 tennis balls. Which control structure would you use?

• For loop

• While loop

• If statement

• Nested while loop

Karel starts at Street 1, Avenue 1, facing East in a 5x5 world. What will happen after this code runs?

move()

putball()

move()

move()

move()

move()

move()

• Karel will end on Street 1, Avenue 2

• This code won’t run because of a syntax error

• Karel will end on Street 1, Avenue 7

• Karel will crash into a wall

How can we improve the following program?

move()

move()

move()

move()

move()

move()

move()

move()

move()

• Break down this program into more functions

• Use a while loop to repeat the move command

• Use a for loop to repeat the move command

• Fix the indentation of this program

In the following code, what would be a good Postcondition to write?

""" Precondition: Karel is on a spot with a tennis ball facing East * Postcondition: ... """ def get_on_top(): turn_left() move() turn_right()

• Karel ends one spot above a tennis ball facing East.

• Karel is on a spot with a tennis ball facing north

• Karel is on the same position but on top of a ball.

• Karel is facing East.

Which of the following commands is a valid Karel command?

• move

• move()

• move;

• move();