Rewrote Stack.java

The previous implementation would show unexpected behaviour when using the values returned by pop() and peek().
Generic type was needed but not used in implementation thus leading to redundancy.
push() had unnecessary return type.

Author: leny-mi

src/main/java/com/dataStructures/Stack.java

@@ -19,42 +19,38 @@ public class Stack<E> implements Serializable {
     /**
      * Position of tail in stack
      */
-
     private int tail = -1;
 
     /**
      * Size of stack at any given time
      */
-
     private int size;
 
     /**
      * Uninitialized array to hold stack elements.
-     * WIll be initialized with initial capacity once the object is created
+     * Will be initialized with initial capacity once the object is created
      */
-    private Object[] elements;
+    private E[] elements;
 
     /**
      * No argument to create stack object with initial capacity
      */
+    @SuppressWarnings("unchecked")
     public Stack() {
-        elements = new Object[INITIAL_CAPACITY];
+        elements = (E[]) new Object[INITIAL_CAPACITY];
     }
 
     /**
      * Method to check if the given stack is empty or not
      */
-
     public boolean empty() {
         return elements == null || size == 0;
     }
 
-
     /**
      * Method to check the element on head without removing it
      */
-
-    public Object peek() {
+    public E peek() {
         if (empty()) {
             throw new EmptyStackException();
         }
@@ -65,13 +61,12 @@ public Object peek() {
     /**
      * Method to remove the top element from stack
      */
-
-    public Object pop() {
+    public E pop() {
         if (empty()) {
             throw new EmptyStackException();
         }
 
-        Object removedElement = elements[tail];
+        E removedElement = elements[tail];
         tail--;
         size--;
         return removedElement;
@@ -80,29 +75,23 @@ public Object pop() {
     /**
      * Method to add element to stack
      */
-    public Object push(Object e) {
-
-        boolean isSuccess = false;
-        if (tail < (INITIAL_CAPACITY - 1)) {
-            tail++;
-            elements[tail] = e;
-        } else {
-            Object[] extendedElements = new Object[INITIAL_CAPACITY + EXTENDED_CAPACITY];
-            System.arraycopy(elements, 0, extendedElements, 0, (tail + 1));
+    @SuppressWarnings("unchecked")
+    public void push(E e) {
+
+        tail = tail + 1;
+        if (tail >= INITIAL_CAPACITY) {
+            E[] extendedElements = (E[]) new Object[INITIAL_CAPACITY + EXTENDED_CAPACITY];
+            System.arraycopy(elements, 0, extendedElements, 0, tail);
             elements = extendedElements;
-            tail++;
-            elements[tail] = e;
         }
-        size++;
-        return e;
-
+        elements[tail] = e;
+        size = size + 1;
     }
 
     /**
      * Method to search for an element in stack
      */
-
-    public int search(Object o) {
+    public int search(E o) {
 
         int index = -1;
         boolean found = false;
@@ -111,7 +100,7 @@ public int search(Object o) {
         }
 
         for (int i = 0; i < size(); i++) {
-            if (elements[i] == o) {
+            if (elements[i].equals(o)) {
                 index = i;
                 found = true;
                 break;