《Java数据结构与算法》笔记-CH5-链表-4用链表实现堆栈

 //用链表实现堆栈
 /**
  * 节点类
  */
 class LinkS {
     private long data;
     public LinkS next;

     public LinkS(long d) {
         this.data = d;
     }

     public String toString() {
         return String.valueOf(data);
     }
 }

 /**
  * 链表类
  */
 class LinkSList {
     private LinkS first;

     public LinkSList() {
         first = null;
     }

     public void insertFirst(LinkS node) {
         node.next = first;
         first = node;
     }

     public LinkS deleteFirst() {
         LinkS temp = first;
         first = first.next;
         return temp;
     }

     public boolean isEmpty() {
         return first == null;
     }

     public String toString() {
         if (isEmpty())
             return "[]";
         StringBuilder sb = new StringBuilder();
         sb.append("[");
         LinkS curr = first;
         while (curr != null) {
             sb.append(curr.toString()).append(",");
             curr = curr.next;
         }
         sb.deleteCharAt(sb.length() - 1);
         sb.append("]");
         return sb.toString();
     }
 }

 /**
  * 栈
  */
 class LinkStack {
     private LinkSList linkList;

     public LinkStack() {
         this.linkList = new LinkSList();
     }

     public void push(LinkS l) {
         this.linkList.insertFirst(l);
     }

     public LinkS pop() {
         return this.linkList.deleteFirst();
     }

     public boolean isEmpty() {
         return this.linkList.isEmpty();
     }

     public String toString() {
         return this.linkList.toString();
     }

     public void display() {
         System.out.println(toString());
     }
 }

 public class LinkStackDemo {
     public static void main(String[] args) {
         LinkStack stack = new LinkStack();
         for (int i = 0; i < 5; i++) {
             LinkS l = new LinkS(i);
             stack.push(l);
             stack.display();
         }
         while (!stack.isEmpty()) {
             System.out.print("pop出" + stack.pop());
             System.out.print("现在栈为:");
             stack.display();
         }
     }
 }