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POCannot find problems with array based deque, but getting outOfBounds exception
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  1. POCannot find problems with array based deque, but getting outOfBounds exception
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    copied!<p>I have been trying to figure this out for an age, but to no avail. I think I must have several problems with my code that I just can't see. I have implemented this using a slightly more complex way before, and was writing it in a simpler form to help a friend in the year below me who is struggling, but I've just ended up getting myself in a muddle!</p> <p>The code is as follows :</p> <pre><code> public class ArrayBasedDeque&lt;EltType&gt; implements Deque&lt;EltType&gt; { private final int CAPACITY = 10; private int capacity; private int end; private EltType deque[]; public ArrayBasedDeque() { this.capacity = CAPACITY; deque = (EltType[]) (new Object[capacity]); } public EltType first() { return deque[0]; } public EltType last() { return deque[end]; } public boolean isEmpty() { return end == 0; } public int size() { return deque.length; } public boolean isFull() { int curSize = size(); return curSize &gt;= capacity; } public void insertFirst(EltType first) { if(!isEmpty()) { EltType[] tempArray; tempArray = (EltType[]) new Object[capacity+1]; for (int i=0;i&lt;deque.length;i++) { tempArray[i+1] = deque[i]; } deque = tempArray; } deque[0] = first; end++; } public void insertLast(EltType last) { if (isFull()){ EltType[] tempArray; tempArray = (EltType[]) new Object[CAPACITY+1]; for (int i=0;i&lt;deque.length;i++) { tempArray[i] = deque[i]; } } deque[end] = last; end++; } public EltType removeFirst() { EltType[] tempArray; EltType returned = deque[0]; tempArray = (EltType[]) new Object[capacity]; for (int i=1;i&lt;capacity;i++) { tempArray[i-1] = deque[i]; } deque = tempArray; end--; return returned; } public EltType removeLast() { EltType[] tempArray; System.out.println(end); EltType returned = deque[end]; tempArray = (EltType[]) new Object[capacity]; for (int i=0;i&lt;deque.length;i++) { tempArray[i] = deque[i]; } deque = tempArray; return returned; } } </code></pre> <p>The problem is that when I call</p> <pre><code>abd.insertFirst( 3 ); abd.insertFirst( 3 ); abd.insertFirst( 3 ); </code></pre> <p>this, it returns an error.</p> <pre><code>java.lang.ArrayIndexOutOfBoundsException: 11 at ArrayBasedDeque.insertFirst(ArrayBasedDeque.java:37) at TestABD.main(TestABD.java:7) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at edu.rice.cs.drjava.model.compiler.JavacCompiler.runCommand(JavacCompiler.java:271) </code></pre> <p>the same is true for the insertLast method. I can't figure it out, and was hoping the scrutinizing gaze of stackOverflow could help me. Thanks a lot !</p>
 

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