一，顺序栈

1.1 IStack栈接口

public interface IStack {public void clear();public boolean isEmpty();public int length();public Object peek(); // 返回栈顶元素public void push(Object x); // 入栈public Object pop(); // 将栈顶元素出栈并返回public void display(); // 输出栈中所有元素
}

1.2，顺序栈增删改查的实现

public class SeqStack implements IStack {private Object[] stackElem; // 顺序栈存储空间private int top; // 指向栈顶元素的下一个存储单元位置private int maxSize; // 空间	public SeqStack(int maxSize) {top = 0;this.maxSize = maxSize;stackElem = new Object[maxSize];}// 将栈置空public void clear() {top = 0; }// 判断栈是否为空public boolean isEmpty() {return top == 0;}// 返回栈中元素的个数public int length() {return top;}// 返回栈顶元素public Object peek() {if (!isEmpty())return stackElem[top - 1];return null;}// 入栈 后进public void push(Object x) {if (top == maxSize) {System.out.println("栈已满");return;}stackElem[top] = x;top ++;}@Overridepublic Object pop() {if (!isEmpty()) {top --;return stackElem[top];}return null;}// 输出栈中所有元素public void display() {for (int i = top - 1; i >= 0; i--) {System.out.print(stackElem[i] + " ");			}System.out.println();}}

1.3，测试顺序栈

public class TestSeqStack {public static void main(String[] args) {SeqStack seqStack = new SeqStack(3);seqStack.push("abc");seqStack.push("def");seqStack.push("ghi");// 返回栈顶元素Object peekEle = seqStack.peek();System.out.println("栈顶元素" + peekEle);// 出栈seqStack.pop();System.out.println("出栈后：");// 遍历栈seqStack.display();}}
/**
栈顶元素ghi
出栈后：
def abc */

二，链栈

2.1，存放数据的结点

public class Node {public Object data; // 存放节点数据值public Node next; // 存放后继节点public Node() {this(null, null);}// 只有节点值的构造函数public Node(Object data) {this(data, null);}// 带有节点值和后继节点的构造函数public Node(Object data, Node next) {this.data = data;this.next = next;}
}

2.2，链栈的实现

// 实现栈接口
public class LinearStack implements IStack {private Node top; // 栈顶元素@Overridepublic void clear() {// 将栈顶置空top = null;}@Overridepublic boolean isEmpty() {// 栈是否为空return top == null;}@Overridepublic int length() {// 栈的长度Node p = top;int length = 0;while (p != null) {p = p.next;length ++;}return length;}@Overridepublic Object peek() {// 返回栈顶元素if (!isEmpty())return top.data;return null;}@Overridepublic void push(Object x) {// 入栈Node s = new Node(x);s.next = top;top = s;}@Overridepublic Object pop() {// 出栈if (isEmpty()) {return null;}Node p = top;top = top.next; // 栈顶的第二个元素顶替return p.data;}@Overridepublic void display() {Node p = top; // p.next 找下一个元素, 要不然死循环while (p != null) {System.out.print(p.data + "\t");p = p.next;}/*while (top != null) {System.out.print(top.data + "\t");top = top.next;}*/}}

2.3测试链栈

public class TestLinearStack {public static void main(String[] args) {// 测试链栈LinearStack ls = new LinearStack();// 入栈ls.push(1);ls.push(3);ls.push(5);ls.push(7);// 返回栈顶元素System.out.println("栈顶元素：" + ls.peek());// 出栈并返回System.out.println("出栈元素：" + ls.pop());// 遍历栈ls.display();}}/**
栈顶元素：7
出栈元素：7
5	3	1
*/