Exam 4: Stacks and Queues

____________________ is a technique used to study the performance of a physical system by using a physical, mathematical, or computer model of the system.

Complete the following code: /** Returns the next element in the queue. Pre: index references the next element to access. Post: index and count are incremented. @return The element with subscript index */ Public E next() { If (!hasNext()) { ____ } E returnValue = theData[index]; Index = (index + 1) % capacity; Count++; Return returnValue; }

____ traversal implies that you will follow one path to the end before embarking on a new path.

A double-linked list requires the same amount of storage as that of a single-linked l ist.

If a LinkedList is used, insertion at the rear of a queue is a(n) ____________________ operation.

Although reallocating an array is an O(n) operation, it is amortized over n items, so the cost per item is O(n²).

If an array is used to implement a Queue, insertion at the rear of the array can be done in ____________________ time.

Complete the following code. /** Insert an item at the rear of the queue. Post: item is added to the rear of the queue. @param item The element to add @return true (always successful) */ Public boolean ____(E item) { // Check for empty queue. If (front == null) { Rear = new Node<E>(item); Front = rear; } else { // Allocate a new node at end, store item in it, and // link it to old end of queue. Rear.next = new Node<E>(item); Rear = rear.next; } Size++; Return true; }

Because interface Queue extends interface ____, a full implementation of the Queue interface must implement all required methods of that interface.

Removal from the front of a queue is a(n) ____________________ operation.

A(n) _____________________ is a data structure in which objects are inserted at one end and removed from the other.

In computer science, queues are used in operating systems to keep track of tasks waiting for a scarce resource and to ensure that the tasks are carried out in the order that they were generated.

If the queue is empty, element method throws a(n) ____________________ exception.

Complete the following code: /** Remove the item accessed by the Iter object - not implemented. */ Public void remove() { Throw new ____(); }

In a(n) ____________________ array, the elements wrap around so that the first element actually follows the last.

Complete the following code: /** Returns the item at the front of the queue without removing it. @return The item at the front if successful; null if not */ Public E ____() { If (size() == 0) Return null; Else Return theQueue.getFirst(); }

____ traversal implies that the nodes visited spread out from the starting point.

Through ____________________, the designers of a new system can estimate the expected performance of the system before they actually build it.

When a queue is implemented using a circular array, insertion at the front is ____.

When a queue is implemented using a circular array, removal from the rear is ____.