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WorksheetsKarel Commands
Total questions: 25
Worksheet time: 13mins
Which of the following commands is a valid Karel command?
move
move( )
move( );
move;
What makes the following command an invalid Karel command?
It should end in a colon rather than a semicolon
It should start with a capital T
This command is correct
The l should be a capital L
Which of the following is the correct way to define a turnRight function in Karel?
function turnRight() {
turnLeft();
turnLeft();
turnLeft();
}
function turnRight() {
turnRight();
turnRight();
turnRight();
}
function turnRight {
turnLeft();
turnLeft();
turnLeft();
}
turnRight function() {
turnLeft();
turnLeft();
turnLeft();
}
Why do we use functions in Karel programs?
To break down our program into smaller parts
To avoid repeating code
To make our program more readable
All of the above
If Karel starts at Street 1 and Avenue 1, facing East, where will Karel be, and what direction will Karel be facing after running the following code? (Assume the world is 10x10 in size)
move();
turnLeft();
putBall();
turnLeft();
turnLeft();
turnLeft();
move();
turnLeft();
Street 3, Avenue 1, Facing North
Street 1, Avenue 4, Facing North
Street 1, Avenue 3, Facing South
Street 1, Avenue 3, Facing North
Karel starts at Street 1 and Avenue 1, facing East. After calling the stairStep function twice, where will Karel be and what direction will Karel be facing? (assume this is a SuperKarel program and the world is 10x10 in size)
function stairStep() {
move();
turnLeft();
move();
turnRight();
}
Street 2, Avenue 2, Facing North
Street 3, Avenue 3, Facing East
Street 3, Avenue 3, Facing West
Street 4, Avenue 4, Facing East
In this code, how many times is the dance function called and how many times is it defined?
function start() {
move();
dance();
move();
move();
turnLeft();
dance();
dance();
}
function dance() {
turnLeft();
move();
turnLeft();
turnLeft();
move();
turnLeft();
}
Called 1 time, defined 1 time
Called 1 time, defined 3 times
Called 3 times, defined 1 time
Called 3 times, defined 3 times
What’s wrong with this code?
function start() {
move();
go();
go();
}
function go() {
move();
move();
}
function go() {
move();
move();
}
The go function is called twice
The go function has a syntax error
The go function has been defined twice
go is not a command that Karel understands
How many total times will Karel move in this program?
function start() {
move();
for (var i = 0; i < 5; i++) {
move();
putBall();
}
}
1
5
6
7
What is wrong with this for loop?
for (var i = 0, i < 10, i + 1) {
move();
}
I. The for loop uses commas instead of semicolons
II. It should say i++ instead of i + 1
I
II
I and II
The for loop is correct
What is the proper format for a single line comment in Karel?
/* This is a comment
This is a comment
// This is a comment
** This is a comment
What does the mystery function do?
function mystery() {
while (noBallsPresent()) {
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
Which of the following is not a valid condition to go in an if statement for Karel?
ballsPresent()
frontIsClear()
leftIsBlocked()
turnLeft()
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 (var i = 0; i < 3; i++) {
if (ballsPresent()) {
takeBall();
} else {
putBall();
putBall();
}
}
0
1
2
6
What condition should be used in this while loop to get Karel to pick up all the tennis balls on the current location?
while (________) {
takeBall();
}
noBallsPresent()
ballsPresent()
frontIsClear()
takeBall()
Why does a programmer indent their code?
Helps show the structure of the code.
Easier for other people to understand.
A key part of good programming style!
All of the above
How can we teach Karel new commands?
For loop
While loop
Define a new function
The start function
Say you want to write a program to have Karel put down 300 tennis balls. Which control structure would you use?
If statement
While loop
For loop
Nested while loop
Karel starts at Street 1, Avenue 1, facing East in a 5x5 world. What will happen after this code runs? Assume this is a SuperKarel program.
move();
move();
turnRight();
move();
Karel ends on street 1, avenue 3
Karel ends on street 2, avenue 3
This code won’t run because of a syntax error
Karel will crash into a wall
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
Karel will end on Street 1, Avenue 7
this code won’t run because of a syntax error
Karel will crash into a wall
What is top down design?
Top down design is a way to use loops and if statements to decompose the problem
Top down design is a way of designing your programs starting with the individual commands first
Top down design is a way of designing your program by starting with the biggest problem and breaking it down into smaller and smaller pieces that are easier to solve.
Top down design is a way that you can create designs on a computer to put on a web page
How can we improve the following program?
function start() {
move();
move();
move();
move();
move();
move();
move();
move();
move();
}
Break down this program into more functions
Use a for loop to repeat the move command
Use a while loop to repeat the move command
Fix the indentation of this program
In the following code below from the Cleanup Karel example, what is the purpose of If Statement #2?
// This program has Karel walk down the
// row and clean up all of the tennis balls
// on the way.
function start() {
while (frontIsClear()) {
// If statement #1
if (ballsPresent()) {
takeBall();
}
move();
}
// If statement #2
if (ballsPresent()) {
takeBall();
}
}
To move the last time
To pick up the ball that is in the last spot
To pick up the ball that is in the last spot, if there is one
To take the ball from all of the positions that have a ball on them
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: ...
*/
function getOnTop() {
turnLeft();
move();
turnRight();
}
Karel is on a spot with a tennis ball facing north
Karel ends one spot above a tennis ball facing East.
Karel is on the same position but on top of a ball.
Karel is facing East.
What is the purpose of using a for loop in code?
To do something if a condition is true
To do something while a condition is true
To repeat something a fixed number of times
To make programs run faster
