When the client attempts to either retrieve or remove an item from an empty stack, our stacks return null. An alternative action is to throw an exception.

a. Modify the interface StackInterface so that an EmptyStackException is thrown in these cases. (This exception is defined in the package java.util.)

b. Modify the array-based implementation of the stack to conform to your changes to StackInterface. Write a program that demonstrates the modifications. c. Repeat Part b for the linked implementation of the stack.

Suppose that we wish to implement the resizing schemes described in Exercises 9 and 10 in addition to the doubling scheme.

a. Write a new version of the array-based stack that lets the client specify the resizing scheme and the associated constant when a stack is created.

b. Write a program that demonstrates the modifications.

c. Discuss the advantages and disadvantages of adding methods that allow the client to change the resize scheme and constant after the stack has been created.

Exercises 9 and 10- Suppose that instead of doubling the size of an array-based stack when it becomes full, you just increase the size of the array by some positive constant k.

a. If you have an empty stack that uses an array whose initial size is k, and you perform n pushes, how many resize operations will be performed? Assume that n > k.

b. What is the average cost of the n push operations?

10- Suppose that instead of doubling the size of an array-based stack when it becomes full, you increase the size of the array by the following sequence 3k, 5k, 7k, 9k, … for some positive constant k.

a. If you have an empty stack that uses an array whose initial size is k, and you perform n pushes, how many resize operations will be performed? Assume that n > k.

b. What is the average cost of the n push operations?