Stack code added

Author: me-shaon

Data Structure/Stack/Stack.php

@@ -0,0 +1,35 @@
+<?php
+/* Stack Implementation in PHP */
+
+//Stack Class
+class Stack{
+    private $_items = array();
+
+    public function push($value = NULL) {
+        array_push($this->_items, $value);
+    }
+
+    public function pop() {
+        return array_pop($this->_items);
+    }
+
+    public function peek() {
+        return end($this->_items);
+    }
+
+	public function size() {
+		return count($this->_items);
+	}
+
+	public function isEmpty() {
+		return empty($this->_items);
+	}
+
+    public function printAll() {
+        foreach ($this->_items as $item) {
+            var_dump($item);
+        }
+    }
+}
+
+?>

Data Structure/Stack/test.php

@@ -0,0 +1,27 @@
+<?php
+/***************** Testing the Stack ***************/
+include('Stack.php');
+
+$stack = new Stack();
+$stack->push(10);
+$stack->push(15);
+
+echo $stack->isEmpty() ? 'Empty' : 'Not Empty';
+echo PHP_EOL;
+
+echo $stack->peek();
+echo PHP_EOL;
+
+echo $stack->pop();
+echo PHP_EOL;
+
+echo $stack->pop();
+echo PHP_EOL;
+
+echo $stack->pop();
+echo PHP_EOL;
+
+echo $stack->isEmpty() ? 'Empty' : 'Not Empty';
+echo PHP_EOL;
+
+?>

README.md

@@ -8,7 +8,7 @@
 - [Introduction to PHP](#introduction)
 - [Data Structure](./Data%20Structure/)
   - Linked List
-  - Stack
+  - [Stack](./Data%20Structure/Stack)
   - Queue
   - Binary Search Tree (BST)
   - Heap