Given the following sequence of stack operations, what is the top item on the stack when the sequence is complete?

Stack s = new Stack();

s.push("x");

s.push("y");

s.pop();

s.push("z");

s.peek();

x

y

z

The stack is empty

2. Given the following sequence of stack operations, what is the top item on the stack when the sequence is complete?

Stack s = new Stack();

s.push(81);

s.push(64);

s.push(49)

while (! s.isEmpty()){

 s.pop();

}

 s.pop()

An error will occur.

81

49

64

3. Suppose you have the following series of queue operations. What items are left on the queue?

Queue q = new Queue();

q.enqueue("dog");

q.enqueue("cat");

q.enqueue("bird");

q.dequeue();

dog, cat, bird

dog, bird

dog, cat

cat, bird

4.

Suppose you have the following series of deque operations. What will be the deque contents?

Deque deq = new Deque();

deq.push-front(97);

deq.push-back(71);

deq.pop-front();

deq.push-front(45);

deq.push-back(68);

68, 97, 45

45, 97, 71

45, 68, 71

45, 71, 68