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POJAVA: Simple pop does only return first item
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  1. POJAVA: Simple pop does only return first item
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    copied!<p>I got following code set up:</p> <pre><code>public class ListStack implements Stack { private class List { List next; Object object; public List(Object o, List n) { object = o; next = n; } } private List firstItem; private int size; public ListStack() { firstItem = new List(null, null); size = 0; } public List getEnd() { List endEl = firstItem; while (endEl.next != null) { endEl = endEl.next; } return endEl; } public boolean push(Object o) { List e1 = new List(o, null); this.getEnd().next = e1; size++; return true; } public Object pop() { if (this.firstItem.next == null) { return null; } else { List endEl; List tempEl; endEl = this.getEnd(); tempEl = firstItem; while (tempEl.next != endEl) { tempEl = tempEl.next; } tempEl.next = null; size--; return tempEl.object; } } public int size() { return size; } public static void main(String[] args) { Stack s = new ListStack(); Object test = new Object(); Object test2 = new Object(); System.out.println("pushing Object test to List: " + s.push(test)); System.out.println("pushing Object test2 to List: " + s.push(test2)); System.out.println("popping Object from List: " + s.pop()); System.out.println("popping Object from List: " + s.pop()); System.out.println("popping Object from List: " + s.pop()); } } </code></pre> <p>And this one:</p> <pre><code> public interface Stack { public int size(); public boolean push(Object o); public Object pop(); } </code></pre> <p>But its only giving me the first object and twice "null" but it should give me the two objects :( where is my mistake? It is asking for the last item and gives it back (.object) but only returns first object adress</p>
 

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