Refactor di tutto lo stack. Manca l'esercizio sulle operazioni matematiche via stack. Sulla coda bisogna implementare da zero FixedArrayQueue e poi la relativa versione senza fullexception in ArrayQueue. Esercizi!

2014-03-17 12:11:39 +01:00
parent d60e74a09c
commit 08069c6b46
17 changed files with 318 additions and 95 deletions
--- a/queue/ArrayQueue.java
+++ b/queue/ArrayQueue.java
@@ -0,0 +1,103 @@
+package queue;
+
+import exceptions.EmptyQueueException;
+
+/**
+ * Created with xgiovio.macbookair.
+ * User: xgiovio
+ * Date: 10/03/14
+ * Time: 15:49
+ */
+public class ArrayQueue<E> implements Queue<E> {
+
+      public ArrayQueue(){
+          queue = (E[])new Object[def_size];
+      }
+
+    public ArrayQueue(int in_size){
+        queue = (E[])new Object[in_size];
+    }
+
+
+    @Override
+    public void enqueue(E element) {
+            if (front == -1){
+                front++;
+            }
+            queue[rear]= element;
+            rear = (rear + 1) % queue.length;
+            if ( rear == front ){
+                //reallocate;
+                E[] new_queue = (E[]) new Object[queue.length * 2];
+                for (int i= 0 ;i<queue.length; i++){
+                    new_queue[i] = queue[front];
+                    front = (front + 1) % queue.length;
+                }
+                rear = queue.length;
+                front = 0;
+                queue = new_queue;
+
+            }
+
+    }
+
+    @Override
+    public E dequeue() throws EmptyQueueException {
+
+        if (front == -1){
+            throw new EmptyQueueException();
+        }else{
+            E temp = queue[front];
+            front++;
+            if (front == rear){
+                front = -1;
+                rear = 0;
+            }
+            return temp;
+        }
+
+
+    }
+
+    @Override
+    public E front() throws EmptyQueueException {
+        if (front == -1){
+            throw new EmptyQueueException();
+        }else{
+            return queue[front];
+        }
+    }
+
+    @Override
+    public boolean isEmpty() {
+        if (size() == 0){
+             return true;
+        }else{
+             return false;
+        }
+    }
+
+    @Override
+    public boolean isFull() {
+        return false;
+    }
+
+    @Override
+    public int size() {
+        if (front == -1){
+            return 0;
+        }
+        if (front < rear){
+              return (rear - front);
+        }else{
+            return (queue.length - front + rear);
+        }
+    }
+
+    int def_size = 100;
+    E[] queue ;
+    int front = -1;
+    int rear = 0;
+
+
+}