update,

it114105/itp4510/Lab03/Lab3.2/ArrayStack.java

@@ -0,0 +1,47 @@
+public class ArrayStack implements Stack {
+    public static final int CAPACITY =1000;
+    private int capacity;
+    private Object[] array;
+    private int top =-1;
+	public ArrayStack() {
+		this(CAPACITY);
+	}
+
+    public ArrayStack(int cap){
+        capacity =cap;
+        array = new Object[capacity];
+    }
+    @Override
+    public int size() {
+        return top+1;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return (top<0);
+    }
+
+    @Override
+    public void push(Object item) throws StackFullException {
+        if(size()==capacity)
+            throw new StackFullException();
+        array[++top]=item;
+    }
+
+    @Override
+    public Object pop() throws StackEmptyException {
+        if(isEmpty())
+            throw new StackEmptyException();
+        Object item =array[top];
+        array[top--]=null;
+        return item;
+    }
+
+    @Override
+    public Object top() throws StackEmptyException {
+        if(isEmpty())
+            throw new StackEmptyException ();
+            return array[top];
+    }
+    
+}