public class ArrayBoundedStack implements StackInterface { protected final int DEFCAP = 100; // default capacity protected T[] elements; // holds stack elements protected int topIndex = -1; // index of top element in stack

public ArrayBoundedStack() { elements = (T[]) new Object[DEFCAP]; }

public ArrayBoundedStack(int maxSize) { elements = (T[]) new Object[maxSize]; }

public void push(T element) // Throws StackOverflowException if this stack is full, // otherwise places element at the top of this stack. { if (isFull()) throw new StackOverflowException("Push attempted on a full stack."); else { topIndex++; elements[topIndex] = element; } }

public void pop() // Throws StackUnderflowException if this stack is empty, // otherwise removes top element from this stack. { if (isEmpty()) throw new StackUnderflowException("Pop attempted on an empty stack."); else { elements[topIndex] = null; topIndex--; } }

public T top() // Throws StackUnderflowException if this stack is empty, // otherwise returns top element of this stack. { T topOfStack = null; if (isEmpty()) throw new StackUnderflowException("Top attempted on an empty stack."); else topOfStack = elements[topIndex]; return topOfStack; }

public boolean isEmpty() // Returns true if this stack is empty, otherwise returns false. { return (topIndex == -1); }

public boolean isFull() // Returns true if this stack is full, otherwise returns false. { return (topIndex == (elements.length - 1)); } }

Add the following methods to the ArrayBoundedStack class, and create a test driver for each to show that they work correctly. In order to practice your array related coding skills, code each of these methods by accessing the internal variables of the Ar rayBoundedStack, not by calling the previously defined public methods of the class. a. String tostring()-creates and returns a string that correctly represents the current stack. Such a method could prove useful for testing and debugging the class and for testing and debugging applications that use the class. Assume each stacked element already provided its own reasonable tostring method. b. int size ()-returns a count of how many items are currently on the stack. Do not add any instance variables to the ArrayBoundedStack class in order to implement this method. c. void popsome (int count)-removes the top count elements from the stack; throws StackUnderflowException if there are less than count elements on the stack. d. boolean swapStart()-if there are less than two elements on the stack returns false; otherwise it reverses the order of the top two elements on the stack and returns true. e. T poptop ( ) -the "classic" pop operation, if the stack is empty it throws StackUnderflowException; otherwise it both removes and returns the top element of the stack