Programming with Karel.

Commenting

Ex. //This moves karel twice

Study test

Which of the following commands is a valid Karel command? move move; move(); move() ANSWERED Question: 2 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 ANSWERED Question: 3 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(); } ANSWERED Question: 4 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 ANSWERED Question: 5 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 ANSWERED Question: 6 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 ANSWERED Question: 7 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 ANSWERED Question: 8 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 ANSWERED Question: 9 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 ANSWERED Question: 10 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 ANSWERED Question: 11 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 ANSWERED Question: 12 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 ANSWERED Question: 13 Which of the following is not a valid condition to go in an if statement for Karel? ballsPresent() frontIsClear() leftIsBlocked() turnLeft() ANSWERED Question: 14 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 ANSWERED Question: 15 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() ANSWERED Question: 16 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 ANSWERED Question: 17 How can we teach Karel new commands? For loop While loop Define a new function The start function ANSWERED Question: 18 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 ANSWERED Question: 19 Karel starts at Street 1, Avenue 1, facing East in a 5x5 world. What will happen after this code runs? 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 ANSWERED Question: 20 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 ANSWERED Question: 21 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 ANSWERED Question: 22 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 ANSWERED Question: 23 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 ANSWERED Question: 24 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. ANSWERED Question: 25 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 ANSWERED CONTINUE

Four loop

for(var i = 0; i < 9; i++){ move(); }

If statements

function start(){ move(); if(frontIsClear()){ move(); } }

If else statement

function start(){ move(); if(frontIsClear()){ move(); }else{ turnLeft(); } }

Function

has a space after with the term wanted to be created then with (){ with then wanted to be done and then } to close it all.

Example on how to make pancakes

move(); makePancakes(); move(); move(); makePancakes(); move(); move(); makePancakes(); move(); function makePancakes() { putBall(); putBall(); putBall(); }