44 lines
1.0 KiB
Java
44 lines
1.0 KiB
Java
// generics/LinkedStack.java
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// (c)2021 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// A stack implemented with an internal linked structure
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public class LinkedStack<T> {
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private static class Node<U> {
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U item;
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Node<U> next;
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Node() { item = null; next = null; }
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Node(U item, Node<U> next) {
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this.item = item;
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this.next = next;
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}
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boolean end() {
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return item == null && next == null;
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}
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}
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private Node<T> top = new Node<>(); // End sentinel
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public void push(T item) {
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top = new Node<>(item, top);
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}
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public T pop() {
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T result = top.item;
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if(!top.end())
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top = top.next;
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return result;
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}
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public static void main(String[] args) {
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LinkedStack<String> lss = new LinkedStack<>();
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for(String s : "Phasers on stun!".split(" "))
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lss.push(s);
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String s;
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while((s = lss.pop()) != null)
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System.out.println(s);
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}
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}
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/* Output:
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stun!
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on
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Phasers
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*/
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