Java 数组、链表实现栈结构

Java Stack

数组实现：

/**
 * Java Stack array implements
 * @param <E>
 */
public class StackX<E> {

    private int mSize = 10;
    private int top = -1;
    private E[] stacks;

    public StackX (){
        stacks = (E[]) new Object[mSize];
    }

    public StackX(int size) {
        mSize = size;
        stacks = (E[]) new Object[mSize];
    }

    /**
     * push stack
     * @param e
     */
    public void push (E e) {
        if (top >= mSize-1) throw new RuntimeException("stack is full.");
        top ++;
        stacks[top] = e;
    }

    /**
     * pop stack
     * @return
     */
    public E pop () {
        return stacks[top--];
    }

    /**
     * check stack
     * @return
     */
    public E peek () {
        if (top < 0 ) throw new RuntimeException("stack is empty, error.");
        return stacks[top];
    }

    public int size () {
        return top + 1;
    }

}

链表结构实现：

/**
 * link implement stack
 * @param <E>
 */
public class LinkStack<E> {

    private Node top;
    private int size;

    /**
     * push stack
     * @param e
     */
    public void push (E e) {
        if (top == null) {
            top = new Node(e);
        } else {
            Node temp = new Node(e);
            temp.next = top;
            top = temp;
        }
        size ++;
    }

    /**
     * pop  top stack element
     * @return
     */
    public E pop () {
        if (top == null) throw new IllegalStateException("the stack is empty, error.");
        Node temp = top;
        top = top.next;
        size --;
        return temp.getElement();
    }

    /**
     * check top stack element
     * @return
     */
    public E peek () {
        if (top == null) throw new IllegalStateException("the stack is empty, error.");
        return top.getElement();
    }

    public int getSize (){
        return size;
    }

    class Node {
        E e;
        Node next;
        public Node(E e) {
            this.e = e;
        }
        public E getElement () {
            return e;
        }
    }

}