Queues

Question 1

What does the enqueue(Object) method do?

Answer 1

Inserts an element at the end of the queue.

Question 2

What does the object dequeue( ) method do?

Answer 2

Removes and returns the element at the

front of the queue.

Question 3

What are the main queue operations?

Answer 3

enqueue( Object ) and Object dequeue( )

Question 4

What does the Object first ( ) method do?

Answer 4

Returns the element at the front without

removing it.

Question 5

What does the integer size( ) method do?

Answer 5

Returns the number of elements stored in the queue.

Question 6

What does the boolean isEmpty( ) method do?

Answer 6

Indicates whether no elements are

stored in the queue.

Question 7

What are the auxiliary methods of a queue?

Answer 7

first( ), size( ), isEmpty( )

Question 8

How do you find the back index of a queue implemented by an array with a size less than array.length?

Answer 8

When the queue has less than array.length elements you can find the back index back = (front + size) % array.length.

Question 9

What’s the pseudocode for enqueue ( catObject )?

Answer 9

back = (front + size) % array.length
array[back] = catObject
size++

Question 10

Whats the pseudocode for dequeue( )?

Answer 10

item = array[front]
front = (front + 1) % array.length
size–
return item