mystack.java

stack code impletemtn by java

/**
 * MyStack.java
 * @version 1.0.0
 * @Hao Chen
 *0236407
 */

/**
 * An implementation of the Stack ADT.
 * In this implementation, we do not grow the stack
 * once it is full.  A better implementation would do so.
 */
 import java.awt.*;
public class MyStack
{
	/**
	 *  Creates a new stack that can hold 1000 elements
	 *
	 */
private int top=-1;
private int cap;
private Object elem[];
public final static int max=1000;
	public MyStack ( )
	{
       this(max);
	}

	/**
	 *
	 * @param initialSize The maximum number of elements to store in the stack
	 */
	public MyStack ( int initialSize )

	{
		cap = initialSize;
		elem= new Object[initialSize];
	}

	/**
	 *  Remove all elements from the stack
	 *
	 */
	public void makeEmpty ()
	{
		for(int i=0; i<cap;i++){
				elem[i]=null;
			}
      top=-1;
	}

	/**
	 * @return is the stack empty?
	 */
public boolean isEmpty ()
	{
		return (top<0);
	}

	/**
	 * @return the number of elements in the stack
	 */
	public int	size ()
	{
		return (top+1);
	}

	/**
	 * Returns the top element on the stack and removes it.
	 * @throws MyStackEmptyException
	 * @return the top element on the stack
	 */
	public Object pop ( ) throws MyStackEmptyException
	{
		if(isEmpty()){
		 throw new MyStackEmptyException("32stack is empty.");}
		 Object k= elem[top];
		 elem[top--]=null;
		 return k;
	}

	/**
	 * This method returns the top element without removing it from
	 * the stack.
	 * @throws MyStackEmptyException
	 * @return the top element on the stack
	 */
	public Object top ( ) throws MyStackEmptyException
	{
		if(isEmpty()){
		 throw new MyStackEmptyException("2313stack is empty.");}
		 return elem[top];
	}
	/**
	 * Push a new element onto the Stack
	 * @throws MyStackFullException
	 */
	public void push ( Object o ) throws MyStackFullException
	{
		if(size()==cap){
		 throw new MyStackFullException("stack is full.");}
		  elem[++top]=o;
	}
}