Java实现队列和栈

package teststack;/** * 基于数组实现的顺序栈 * @param <E> */public class Stack<E> {    private Object[] data = null;    private int maxSize=0;   //栈容量    private int top =-1;  //栈顶指针        /**     * 构造函数：根据给定的size初始化栈     */    Stack(){        this(10);   //默认栈大小为10    }        Stack(int initialSize){        if(initialSize >=0){            this.maxSize = initialSize;            data = new Object[initialSize];            top = -1;        }else{            throw new RuntimeException("初始化大小不能小于0：" + initialSize);        }    }        //判空    public boolean empty(){        return top==-1 ? true : false;    }        //进栈,第一个元素top=0；    public boolean push(E e){        if(top == maxSize -1){            throw new RuntimeException("栈已满，无法将元素入栈！");        }else{            data[++top]=e;            return true;        }        }        //查看栈顶元素但不移除    @SuppressWarnings("unchecked")public E peek(){        if(top == -1){            throw new RuntimeException("栈为空！");        }else{            return (E)data[top];        }    }        //弹出栈顶元素    public E pop(){        if(top == -1){            throw new RuntimeException("栈为空！");        }else{        E e = (E)data[top];        data[top--]=null;        return e;        }    }        //返回对象在堆栈中的位置，以 1 为基数    public int search(E e){        int i=top;        while(top != -1){            if(peek() != e){                top --;            }else{                break;            }        }        int result = top+1;        top = i;        return result;          }}

栈的链式存储结构实现：

package linkstack;public class LinkStack<E> {    //链栈的节点    private class Node<E>{        E e;        Node<E> next;        public Node(){}        public Node(E e, Node next){            this.e = e;            this.next = next;        }    }        private Node<E> top;   //栈顶元素    private int size;  //当前栈大小        public LinkStack(){        top = null;    }        //当前栈大小    public int length(){        return size;    }        //判空    public boolean empty(){        return size==0;    }        //入栈：让top指向新创建的元素，新元素的next引用指向原来的栈顶元素    public boolean push(E e){        top = new Node(e,top);        size ++;        return true;    }        //查看栈顶元素但不删除    public E peek(){        if(empty()){            throw new RuntimeException("空栈异常！");        }else{            return top.e;        }    }        //出栈    public E pop(){        if(empty()){            throw new RuntimeException("空栈异常！");        }else{            Node<E> value = top; //得到栈顶元素            top = top.next; //让top引用指向原栈顶元素的下一个元素             value.next = null;  //释放原栈顶元素的next引用            size --;            return value.e;        }    }}

LinkedList实现队列的实现

import java.util.LinkedList;/** * 基于LinkedList实现栈 * 在LinkedList实力中只选择部分基于栈实现的接口 */public class StackList<E> {    private LinkedList<E> ll = new LinkedList<E>();        //入栈    public void push(E e){        ll.addFirst(e);    }        //查看栈顶元素但不移除    public E peek(){        return ll.getFirst();    }        //出栈    public E pop(){        return ll.removeFirst();    }        //判空    public boolean empty(){        return ll.isEmpty();    }        //打印栈元素    public String toString(){        return ll.toString();    }}