前言
听着天籁，我是个音乐迷。时间充实着，会过得很快。我马上也可以到傍晚的时候去乐室吹我心爱的萨克斯。
嘟嘟嘟... 我会吹一首简单的歌咯，哈哈我想到了一个神奇的比喻，待会说。
栈ADT模型（又称LIFO表）
栈（stack）插入和删除只能在一个位置上进行的表。该位置是表的末端但是叫做栈的顶（top）。基本操作：进栈（push相当于插入）和出栈（pop相当于删除）。又称LIFO表，后进先出。
相当于
就想快速呼吸一样。先吸进来的空气，先呼出去。
你是否记住了？
栈的源码和数组实现
java.util.Stack
不得不申明下，小朽研究不深，如果大家看到了希望能指点指点我。有些时候，说错了，我马上会改正的。谢谢。先介绍类的结构图
下面是源码 java.util.Stack
1 /* 2 * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved. 3 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 * 12 * 13 * 14 * 15 * 16 * 17 * 18 * 19 * 20 * 21 * 22 * 23 * 24 */ 25 26 package java.util; 27 28 /** 29 * TheStackclass represents a last-in-first-out 30 * (LIFO) stack of objects. It extends class Vector with five 31 * operations that allow a vector to be treated as a stack. The usual 32 * push and pop operations are provided, as well as a 33 * method to peek at the top item on the stack, a method to test 34 * for whether the stack is empty, and a method to search 35 * the stack for an item and discover how far it is from the top. 36 *37 * When a stack is first created, it contains no items. 38 * 39 *
A more complete and consistent set of LIFO stack operations is 40 * provided by the {
@link Deque} interface and its implementations, which 41 * should be used in preference to this class. For example: 42 *{ @code 43 * Deque44 * 45 * @author Jonathan Payne 46 * @since JDK1.0 47 */ 48 public 49 class Stackstack = new ArrayDeque ();} extends Vector { 50 /** 51 * Creates an empty Stack. 52 */ 53 public Stack() { 54 } 55 56 /** 57 * Pushes an item onto the top of this stack. This has exactly 58 * the same effect as: 59 * 61 * 62 * @param item the item to be pushed onto this stack. 63 * @return the60 * addElement(item)itemargument. 64 * @see java.util.Vector#addElement 65 */ 66 public E push(E item) { 67 addElement(item); 68 69 return item; 70 } 71 72 /** 73 * Removes the object at the top of this stack and returns that 74 * object as the value of this function. 75 * 76 * @return The object at the top of this stack (the last item 77 * of the Vector object). 78 * @throws EmptyStackException if this stack is empty. 79 */ 80 public synchronized E pop() { 81 E obj; 82 int len = size(); 83 84 obj = peek(); 85 removeElementAt(len - 1); 86 87 return obj; 88 } 89 90 /** 91 * Looks at the object at the top of this stack without removing it 92 * from the stack. 93 * 94 * @return the object at the top of this stack (the last item 95 * of the Vector object). 96 * @throws EmptyStackException if this stack is empty. 97 */ 98 public synchronized E peek() { 99 int len = size();100 101 if (len == 0)102 throw new EmptyStackException();103 return elementAt(len - 1);104 }105 106 /**107 * Tests if this stack is empty.108 *109 * @returntrueif and only if this stack contains110 * no items;falseotherwise.111 */112 public boolean empty() {113 return size() == 0;114 }115 116 /**117 * Returns the 1-based position where an object is on this stack.118 * If the object o occurs as an item in this stack, this119 * method returns the distance from the top of the stack of the120 * occurrence nearest the top of the stack; the topmost item on the121 * stack is considered to be at distance 1. The equals122 * method is used to compare o to the123 * items in this stack.124 *125 * @param o the desired object.126 * @return the 1-based position from the top of the stack where127 * the object is located; the return value-1128 * indicates that the object is not on the stack.129 */130 public synchronized int search(Object o) {131 int i = lastIndexOf(o);132 133 if (i >= 0) {134 return size() - i;135 }136 return -1;137 }138 139 /** use serialVersionUID from JDK 1.0.2 for interoperability */140 private static final long serialVersionUID = 1224463164541339165L;141 }
①Pushes an item onto the top of this stack.
public E push(E item) { addElement(item); return item; } 从类的结构图可以看出,addElement是Stack父类Vector封装，用于一切其子类的封装。
#Adds the specified component to the end of this vector
public synchronized void addElement(E obj) { modCount++; ensureCapacityHelper(elementCount + 1); elementData[elementCount++] = obj; }
②Removes the object at the top of this stack and returns the onject that object as the value of this function
public synchronized E pop() { E obj; int len = size(); obj = peek(); removeElementAt(len - 1); return obj; } 同样，跟addElement一样removeElementAt存在Vector
#Deletes the component at the specified index.
public synchronized void removeElementAt(int index) { modCount++; if (index >= elementCount) { throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount); } else if (index < 0) { throw new ArrayIndexOutOfBoundsException(index); } int j = elementCount - index - 1; if (j > 0) { System.arraycopy(elementData, index + 1, elementData, index, j); } elementCount--; elementData[elementCount] = null; /* to let gc do its work */ } But,这个是什么 peek（），别慌它也是存在Stack类中下面我们讲这个
③Looks at the object at the top of this stack without remocing it
public synchronized E peek() { int len = size(); if (len == 0) throw new EmptyStackException(); return elementAt(len - 1); } 跟addElement,removeElementAt一样，elementAt存在Vector
#Returns the component at the specified index.
public synchronized E elementAt(int index) { if (index >= elementCount) { throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount); } return elementData(index); }
④Tests if this stack is empty
public boolean empty() { return size() == 0; } size() 来源于Vector,用于获取大小
⑤Stack中其他，就不做介绍罗列下
void Stack() //create an empty stack int search(Object o) //return the 1 - based position where an obj is on this stack
数组实现
package sedion.jeffli.bean;/** * qq 1928348753 * blog http://www.cnblogs.com/Alandre/ * @author Jeff Li */public class myS { Object[] data; int maxSize; int top; public myS(int maxSize) { this.maxSize = maxSize; data = new Object[maxSize]; top = -1; } /** * 获取堆栈长度 * @return 堆栈长度 */ public int getSize() { return maxSize; } /** * 返回栈中元素的个数 * @return 栈中元素的个数 */ public int getElementCount() { return top; } /** * 判断栈空 * @return 栈空 */ public boolean isEmpty() { return top == -1; } /** * 判断栈满 * @return 栈满 */ public boolean isFull() { return top+1 == maxSize; } /** * 依次加入数据 * @param data 加入的数据 * @return 添加是否成功 */ public boolean push(Object data) { if(isFull()) { System.out.println("栈已满!"); return false; } this.data[++top] = data; return true; } /** * 从栈中取出数据 * @return 取出的数据 */ public Object pop() throws Exception{ if(isEmpty()) { throw new Exception("栈已空!"); } return this.data[top--]; } /** * 返回栈顶元素 * @return */ public Object peek() { return this.data[getElementCount()]; } public static void main(String[] args) throws Exception { myS stack=new myS(1000); stack.push(new String("1")); stack.push(new String("2")); stack.push(new String("3")); stack.push(new String("4")); stack.push(new String("5")); System.out.println("栈顶元素"+stack.peek()); while(stack.top>=0) { System.out.println("Position["+stack.top+"]:"+stack.pop()); } } }
栈的应用
四则运算，计算器编程。这些，我想原理才是重要的。
这是一些资料共享应用
寄读者，寄知识来源
读者，你好！你我不相识，谢谢你们支持。我的梦想会越来越接近。keep on，共勉！
知识来源