栈-顺序存储-Java实现

package com.wrh.lab.dataStructure.stackAndQueue;

/**
 * the interface of the SeqStack
 * @author wrh
 *
 * @param <E>
 */
public interface Stack<E> {
    
    /**
     * push the element to the stack
     * @param element
     */
    public void push(E element);
    
    /**
     * pop the element from the stack and
     * return the pop element
     */
    public E pop();
    
    /**
     * 
     * @return the top value
     */
    public E getTop();
    
    /**
     * 
     * @return true for empty and false for not empty
     */
    public boolean isEmpty();
    
    /**
     * clear the stack
     */
    public void clear();
    
}

 

package com.wrh.lab.dataStructure.stackAndQueue;

/**
 * 
 * @author wrh
 * the stack node
 */
public class StackNode<E> {
    private E element;
    private StackNode<E> next;
    
    /**
     * constructor
     */
    public StackNode() {
        element = null;
        next = null;
    }
    
    public StackNode(E element, StackNode<E> next) {
        this.element = element;
        this.next = next;
    }

    public E getElement() {
        return element;
    }

    /**
     * @param element
     */
    public void setElement(E element) {
        this.element = element;
    }
    
    public StackNode<E> getNext() {
        return next;
    }

    public void setNext(StackNode<E> next) {
        this.next = next;
    }
    
}

 

package com.wrh.lab.dataStructure.stackAndQueueImpl;

import com.wrh.lab.dataStructure.stackAndQueue.Stack;

public class SeqStackImpl<E> implements Stack<E> {
    private static final int defaultSize = 3;
    private  int size;    //max size of the stack
    private int top;    //index for top object
    private E[] listArray;    //array hoding stack objects
    private static final int MAX_SIZE = 7;
    /**
     * constructor init a stack for the size defaultSize
     */
    public SeqStackImpl() {
        size = defaultSize;
        top = -1;
        listArray = (E[]) new Object[size];
    }
    
    /**
     * constructor 
     * init a stack for the size of size
     * @param size
     */
    public SeqStackImpl(int size) {
        if (size < 1 || size > MAX_SIZE) {
            System.out.println("the size is not vailable");
        } else {
            this.size = size;
            top = -1;
            listArray = (E[]) new Object[size];
        }
    }
    

    @Override
    public void push(E element) {
        if (size < MAX_SIZE && top < size) {
            listArray[++top] = element;
        } else if (top < MAX_SIZE){
            resizeList(listArray);
            listArray[++top] = element;
        } else {
            System.out.println("the stack is full! ");
        }
    }

    @Override
    public E pop() {
        if (isEmpty()) {    //if the stack is empty
            System.out.println("the stack is empty");
            return null;
        } else {
            
            return listArray[top--];
            
        }
    }

    @Override
    public E getTop() {
        return listArray[top];
    }
    
    /**
     * resize the list 
     * @param entry
     */
    public void resizeList(E[] list) {
        int resize = size * 3 / 2 +1;
        Object[] seqList_upp = new Object[resize];
        System.arraycopy(list,0,seqList_upp,0,size);
        this.listArray = (E[]) seqList_upp;
    }

    @Override
    public boolean isEmpty() {
        return 0 == top;
    }

    @Override
    public void clear() {
        top = 0;
    }
    
    public static void main(String[] args) {
        Stack<Integer> s = new SeqStackImpl<Integer>(5);
        s.push(1);
        s.push(2);
        s.push(3);
        s.push(4);
        s.push(5);
        System.out.println(s.isEmpty());
        System.out.println(s.pop());
        System.out.println(s.pop());
        s.clear();
        System.out.println(s.pop());
    }

}