Add new Stack class

Author: technicalguru

src/TgUtils/Stack.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace TgUtils;
+
+class Stack {
+
+	protected $stack;
+
+	public function __construct(...$values) {
+		$this->stack = array();
+		foreach ($values AS $value) {
+			$this->push($value);
+		}
+	}
+
+	public function isEmpty() {
+		return count($this->stack) == 0;
+	}
+
+	public function size() { 
+		 return count($this->stack);
+	}
+
+	public function push($value) {
+		if ($value != NULL) array_push($this->stack, $value);
+		else throw new \Exception('Cannot push NULL element to stack');
+	}
+
+	public function pop() {
+		if (!$this->isEmpty()) {
+			return array_pop($this->stack);
+		}
+		return NULL;
+	}
+
+	public function peek() {
+		if (!$this->isEmpty()) {
+			return $this->stack[count($this->stack)-1];
+		}
+		return NULL;
+	}
+}
+