链表模拟栈

定义节点 

class Node {var num: Int = _var next: Node = _def this(num: Int) {thisthis.num = num}override def toString: String = s"num=[${this.num}]"
}

定义方法

class LinkStack {private var head = new Node(0)def getHead: Node = head//判断是否为空def isEmpty: Boolean = {head.next == null}//无需判断是否为满//查看当前链表def list(): Unit = {if (isEmpty) {println(s"栈已空")return}var temp = head.nextwhile (temp.next != null) {println(s"${temp}")temp = temp.nextThread.sleep(500)}}//入栈def push(value: Int): Unit = {if (isEmpty) head.next = new Node(1)//使用头插法val newNode = new Node(value)newNode.next = head.nexthead.next = newNode}//出栈def pop(): Int = {if (isEmpty) throw new RuntimeException("栈空")val temp = head.nextif (temp.next != null) {println(s"弹栈=>${temp.num}")head = temp.next} else {println(s"弹栈=>${temp.num}")}temp.num}
}

主函数

package Algotithmobject LinkedListStackDemo {def main(args: Array[String]): Unit = {val stack = new LinkStackstack.push(1)stack.push(3)println(s"原链表=====")stack.list()println(s"弹栈一次=====")stack.pop()stack.list()println(s"弹栈二次=====")stack.pop()stack.list()}}

结果 

总结

1、入栈时使用头插法，将新节点插入在 head头节点后面

2、 pop出栈 时需要对当前链表进行非空判定。如果取出后节点为空，则不需要对 head.next 进行赋值