/** * This class implements a Stack using a regular array. *

* A stack is exactly what it sounds like. An element gets added to the top of * the stack and only the element on the top may be removed. This is an example * of an array implementation of a Stack. So an element can only be added/removed * from the end of the array. In theory stack have no fixed size, but with an * array implementation it does. * * @author Unknown */ public class StackArray { /** * Main method * * @param args Command line arguments */ public static void main(String[] args) { // Declare a stack of maximum size 4 StackArray myStackArray = new StackArray(4); // Populate the stack myStackArray.push(5); myStackArray.push(8); myStackArray.push(2); myStackArray.push(9); System.out.println("*********************Stack Array Implementation*********************"); System.out.println(myStackArray.isEmpty()); // will print false System.out.println(myStackArray.isFull()); // will print true System.out.println(myStackArray.peek()); // will print 9 System.out.println(myStackArray.pop()); // will print 9 System.out.println(myStackArray.peek()); // will print 2 } /** * The max size of the Stack */ private int maxSize; /** * The array representation of the Stack */ private int[] stackArray; /** * The top of the stack */ private int top; /** * Constructor * * @param size Size of the Stack */ public StackArray(int size) { maxSize = size; stackArray = new int[maxSize]; top = -1; } /** * Adds an element to the top of the stack * * @param value The element added */ public void push(int value) { if (!isFull()) { // Checks for a full stack top++; stackArray[top] = value; } else { resize(maxSize * 2); push(value); // don't forget push after resizing } } /** * Removes the top element of the stack and returns the value you've removed * * @return value popped off the Stack */ public int pop() { if (!isEmpty()) { // Checks for an empty stack return stackArray[top--]; } if (top * Doesn't delete elements in the array * but if you call push method after calling * makeEmpty it will overwrite previous * values */ public void makeEmpty() { // Doesn't delete elements in the array but if you call top = -1; // push method after calling makeEmpty it will overwrite previous values } }