Basic JavaScript Review

Why do programmers use variables?

• Because they are lazy and don’t want to write out equations every time

• It allows the programmer to reuse multiple lines of code

• They are a way to document functions

• To store values to easily reuse later and make code easier to read and understand

If you were given the following variables:

var distance = 2;

var time = 30;

What line of code would print the speed in km/hr if the distance is given in km and the time is given in minutes? (Speed = distance/time)

• println(distance/(time/60));

• println(distance/time);

• println(distance*(time*60));

• println(distance*time);

What is printed to the screen if the user enters ‘5’ when the following program is run?

var userNum = readInt("Enter your favorite number: ");

var calculatedNum = (userNum * userNum) + userNum;

println(calculatedNum);

• 5

• 30

• 25

• 50

A store has 20 apples in its inventory. How can you store this information in a JavaScript variable?

• var numApples == 20;

• 20 = numApples;

• var numApples = 20;

• var num apples = 20;

You want to read input from the user to know how many apples they would like to buy. Which statement should you use to read in a number from the user?

• var applesToBuy = readLine("How many apples would you like? ");

• var applesToBuy = println("How many apples would you like? ");

• var applesToBuy = readInt("How many apples would you like? ");

• var applesToBuy = nextInt("How many apples would you like? ");

You are splitting up all of your apples equally between 3 people. Which statement below will calculate how many apples will be left over?

• var leftOver = numApples / 3;

• var leftOver = numApples % 3;

• var leftOver = 3 / numApples;

• var leftOver = 3 / numApples;

In order to write the function rollDice() for a game, I need to generate and store a random integer between 1 and 6. Which statement below will accomplish this task?

• var diceRoll = Randomizer.nextInt(1,6);

• var diceRoll = Randomizer.nextInt(0,7);

• var diceRoll = Randomizer.nextNum(1,6);

• var diceRoll = Randomizer(1,6);

What is printed to the screen when the following program is run?

var num = 13 % 3;

println(num);

• 1

• 2

• 3

• 4

Which of the following choices is a properly formed JavaScript variable name, meaning it is both legal in the JavaScript language and considered good style?

• user_age

• UserAge

• userAge

• User age

What is Top Down Design?

• Starting with the most specific problems and then working up to solve the big problem

• Working from the top of your program and coding down to the bottom

• Starting with the biggest problem and then working down to solve the more specific problems

• Implementing all of the functions first, then putting them together in the start function