/** * Implementation of a stack using nodes. * Unlimited size, no arraylist. * * @author Kyler Smith, 2017 */ public class NodeStack<Item> { /** * Entry point for the program. */ public static void main(String[] args) { NodeStack<Integer> Stack = new NodeStack<Integer>(); Stack.push(3); Stack.push(4); Stack.push(5); System.out.println("Testing :"); Stack.print(); // prints : 5 4 3 Integer x = Stack.pop(); // x = 5 Stack.push(1); Stack.push(8); Integer y = Stack.peek(); // y = 8 System.out.println("Testing :"); Stack.print(); // prints : 8 1 4 3 System.out.println("Testing :"); System.out.println("x : " + x); System.out.println("y : " + y); } /** * Information each node should contain. * @value data : information of the value in the node * @value head : the head of the stack * @value next : the next value from this node * @value previous : the last value from this node * @value size : size of the stack */ private Item data; private static NodeStack<?> head; private NodeStack<?> next; private NodeStack<?> previous; private static int size = 0; /** * Constructors for the NodeStack. */ public NodeStack() { } private NodeStack(Item item) { this.data = item; } /** * Put a value onto the stack. * * @param item : value to be put on the stack. */ public void push(Item item) { NodeStack<Item> newNs = new NodeStack<Item>(item); if(this.isEmpty()) { NodeStack.setHead(new NodeStack<>(item)); newNs.setNext(null); newNs.setPrevious(null); } else { newNs.setPrevious(NodeStack.head); NodeStack.head.setNext(newNs); NodeStack.head = newNs; } NodeStack.setSize(NodeStack.getSize() + 1); } /** * Value to be taken off the stack. * * @return item : value that is returned. */ public Item pop() { Item item = (Item) NodeStack.head.getData(); NodeStack.head = NodeStack.head.getPrevious(); NodeStack.head.setNext(null); NodeStack.setSize(NodeStack.getSize() - 1); return item; } /** * Value that is next to be taken off the stack. * * @return item : the next value that would be popped off the stack. */ public Item peek() { return (Item) NodeStack.head.getData(); } /** * If the stack is empty or there is a value in. * * @return boolean : whether or not the stack has anything in it. */ public boolean isEmpty() { return NodeStack.getSize() == 0; } /** * Returns the size of the stack. * * @return int : number of values in the stack. */ public int size() { return NodeStack.getSize(); } /** * Print the contents of the stack in the following format. * * x <- head (next out) * y * z <- tail (first in) * . * . * . * */ public void print() { for(NodeStack<?> n = NodeStack.head; n != null; n = n.previous) { System.out.println(n.getData().toString()); } } /** Getters and setters (private) */ private NodeStack<?> getHead() { return NodeStack.head; } private static void setHead(NodeStack<?> ns) { NodeStack.head = ns; } private NodeStack<?> getNext() { return next; } private void setNext(NodeStack<?> next) { this.next = next; } private NodeStack<?> getPrevious() { return previous; } private void setPrevious(NodeStack<?> previous) { this.previous = previous; } private static int getSize() { return size; } private static void setSize(int size) { NodeStack.size = size; } private Item getData() { return this.data; } private void setData(Item item) { this.data = item; } }
栈算是比较简单的,pop push peek ,但是用的地方很多,方法栈,变量名等都是压栈弹栈
原文地址:https://www.cnblogs.com/CherryTab/p/11939117.html
时间: 2024-10-10 00:44:16