1.21.1 Introduction to Programming Quiz

Question: 25 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

// This is a comment

Question: 3 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(); } } JavaScript 0 1 2 6

1

Question: 23 How many total times will Karel move in this program? function start() { move(); for (var i = 0; i < 5; i++) { move(); putBall(); } } JavaScript 1 5 6 7

6

Question: 24 What is wrong with this for loop? for (var i = 0, i < 10, i + 1) { move(); } JavaScript A. The for loop uses commas instead of semicolons B. It should say i++ instead of i + 1 A B A and B The for loop is correct

A and B

Question: 7 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

For loop

Question: 13 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(); } JavaScript 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.

Karel ends one spot above a tennis ball facing East.

Question: 21 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(); } JavaScript Called 1 time, defined 1 time Called 1 time, defined 3 times Called 3 times, defined 1 time Called 3 times, defined 3 times

Called 3 times, defined 1 time

Question: 6 How can we teach Karel new commands? For loop While loop Define a new function The start function

Define a new function

Question: 18 Why do we use functions in Karel programs? Break down our program into smaller parts Avoid repeating code Make our program more readable All of the above

All of the above

Question: 5 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

All of the above

What does the mystery function do? function mystery() { while (noBallsPresent()) { move(); } } JavaScript Karel moves until it is on a ball If there is no ball present, Karel will move one time and stop. Karel moves until it puts down a ball Karel checks if there is no ball on the current spot and then moves once

Karel moves until it is on a ball

Question: 8 Super Karel starts at Street 1, Avenue 1, facing East in a 5x5 world. What will happen after this code runs? move(); move(); turnRight(); move(); JavaScript 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 will crash into a wall

Question: 19 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(); JavaScript Street 3, Avenue 1, Facing North Street 1, Avenue 4, Facing North Street 1, Avenue 3, Facing South Street 1, Avenue 3, Facing North

Street 1, Avenue 3, Facing North

Question: 20 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(); } JavaScript Street 2, Avenue 2, Facing North Street 3, Avenue 3, Facing East Street 3, Avenue 3, Facing West Street 4, Avenue 4, Facing East

Street 3, Avenue 3, Facing East

Question: 22 What's wrong with this code? function start() { move(); go(); go(); } function go() { move(); move(); } function go() { move(); move(); } JavaScript 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

The go function has been defined twice

Question: 16 What makes the following command an invalid Karel command? turnleft(); It should end in a colon rather than a semicolon The l should be a capital L It should start with a capital T This command is correct

The l should be a capital L

Question: 9 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(); JavaScript 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

This code won't run because of a syntax error

Question: 12 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(); } } JavaScript 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

To pick up the ball that is in the last spot, if there is one

Question: 14 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

To repeat something a fixed number of times

Question: 10 What is top down design? 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 Top down design is a way of designing your programs starting with the individual commands first 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 program by starting with the biggest problem and breaking it down into smaller and smaller pieces that are easier to solve.

Question: 11 How can we improve the following program? function start() { move(); move(); move(); move(); move(); move(); move(); move(); move(); } JavaScript 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

Use a for loop to repeat the move command

Question: 4 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(); } JavaScript noBallsPresent() ballsPresent() frontIsClear() takeBall()

ballsPresent()

Question: 17 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(); }

function turnRight() { turnLeft(); turnLeft(); turnLeft(); }

Question: 15 Which of the following commands is a valid Karel command? move move; move(); move()

move();

Question: 2 Which of the following is not a valid condition to go in an if statement for Karel? ballsPresent() frontIsClear() leftIsBlocked() turnLeft()

turnLeft()