Data Structures

Question 1

What does the acronym LIFO mean?

Answer 1

Last-In-First-Out operations: the last thing pushed onto the stack is the first thing that can be popped out.

Question 2

What methods are available on a Stack data structure?

Answer 2

pop() - pops the “top” value off of the stack.
push() - pushes an item to the “top” of the stack
peek() - returns the “top” value without modifying it

Question 3

What must you do to access the value at an arbitrary point in a stack (not just the “top”)?

Answer 3

Start at the top and traverse through with the next property

Question 4

What does the acronym FIFO mean?

Answer 4

First-In-First-Out operations: the first thing in enqueued onto the queue is the first thing that can be dequeued out.

Question 5

What methods are available on a Queue data structure?

Answer 5

enqueue(value) - adds a value to the “back” of the queue
dequeue() - removes the “front” value from the queue and returns it
peek() - returns the “front” value of the queue without removing it

Question 6

What must you do to access the value at an arbitrary point in a queue (not just the “front”)?

Answer 6

dequeue() until you get to the point

Question 7

What must the return value ofmyFunctionbe if the following expression is possible? myFunction()();

Answer 7

A function

Question 8

What does this code do? const wrap = value => () => value;

Answer 8

wrap(1)(); //1
wrap(2)(); //2

Returns the value

wrap(value) {
return () => value;
};

function wrap(value) {
return function() {
return value;
};
};

Question 9

In JavaScript, when is a function’s scope determined; when it is called or when it is defined?

Answer 9

Defined

Question 10

What allows JavaScript functions to “remember” values from their surroundings?

Answer 10

Closures