JavaScript Quiz Flashcards

Flashcards based on JavaScript quiz questions and answers.

Which of the following is a valid for loop in JavaScript?

for (var i = 0; i < 5; i++) { console.log(i); }

What is an example of a keyboard event in JavaScript?

keydown

What does the following code do? keyDownMethod(keyFunction); function keyFunction(event) { console

It logs the key pressed on the keyboard

How many value pairs are logged by this loop? for (var i = 0; i < 3; i++) { for (var j = 0; j < 2; j++) { consol

6

What does the && operator represent?

Logical AND

What is the purpose of nested for loops?

To perform repetitive tasks in a grid-like structure

What is a boolean value?

A value that is either true or false

How can you make a for loop count backwards from 10 to 0?

for (var i = 10; i >= 0; i--)

How would you fix this infinite loop? var counter = 0; while (counter < 5) { console.log(counter); }

Add counter++; inside the loop

What does this code print? for (int i = 0; i < 10; i++) { console.log(Randomizer.nextInt(1, 2)); }

It prints either 1 or 2 randomly each of ten times

What's the bug in this code? var count = 0; while (count < 5) { console.log(count); }

The loop will run infinitely

Why are random numbers useful in programming?

They help simulate unpredictable real-world events

What's the bug in this loop-and-a-half structure? while (true) { var input = readLine("Enter a number:");

readLine() doesn't return a number

Which scenario is a good use of a loop-and-a-half?

Searching through a list until a specific item is found

Which statement about infinite loops is true?

They can cause the program to freeze or crash

What does this do-while loop output if number is initially 5?

5

What is the output of addNumbers(5, 10)?

15

What is the output of this code? multiply(2, 5);

10

What does double(3) return?

6

What will isEven(4) return?

true

How many parameters can a function take?

As many as you want

Why use a function with parameters rather than fixed values?

To allow flexibility and reuse of the function with different inputs

What happens if you define parameters but call the function without arguments?

The parameters will be undefined

Which is a function with multiple parameters?

function calculateArea(width, height) { return width * height; }

How do local variables help organize code?

They prevent naming conflicts between different parts of the program

What is a local variable?

A variable that is declared within a function and only accessible within that function

What does this code output? var globalVar = "I am a variable."; function testScope() { console.log(globa

"I am a variable."

Why are APIs important for developers?

They allow for code reuse and simplify complex operations

Which variable should be declared globally?

A constant value used throughout the program

What is an API (Application Programming Interface)?

A set of functions and tools that allow different software components to communicate

How is Karel's move() an example of an API?

It abstracts complex movement logic into a simple function call

What will this code output? var count = 0; function increment() { var myLocal = count; count++; } increm

1

Which task would require traversing a list?

Finding out how many even numbers there are in the list

What is the length property of an array used for?

To determine the number of elements in the array

What will this code print? var arr = [1, 2, 3, 4]; arr[1] = arr[3] - arr[1]; println(arr);

[1, 2, 3, 4]

"Dali" is located at which index in this list: ["Ada", "Bao", "Cedric", "Dali", "Elena"]

3

What should replace to print all list items?

i < list.length

What is the value of index in this code?

1

How to remove the last item in an array and store it?

var lastTask = tasks.pop();

Which element is at index 1 in ["carrots", "peas", "sprouts", "okra"]?

"peas"