diff --git a/CPlusPlus/intro/main.cpp b/CPlusPlus/intro/main.cpp
index 109770c..b17a6ef 100644
--- a/CPlusPlus/intro/main.cpp
+++ b/CPlusPlus/intro/main.cpp
@@ -1,6 +1,8 @@
 #include <iostream>
 #include <Windows.h>
 #include <memory>
+#include <vector>
+#include <list>
 #include "functions.h"
 #include "ClassA.h"
 #include "ClassB.h"
@@ -115,8 +117,8 @@ int main()
 	//cout << n << endl;
 	//classB.GetNumber();
 
-	IPrintable* pPrintable = nullptr;
-	pPrintable = new ClassB();
+	//IPrintable* pPrintable = nullptr;
+	//pPrintable = new ClassB();
 	//(*pPrintable).Print();
 	//pPrintable->Print(); // same line as above, but simpler
 	////ClassB* pClassB2 = (ClassB*)pPrintable; // C-Cast, CAUTION: DANGER!!!
@@ -138,7 +140,39 @@ int main()
 
 	//delete pPrintable;
 	//pPrintable = nullptr;
-	safeDelete(pPrintable);
+	//safeDelete(pPrintable);
+
+	//vector<int> numbers = { 0, 1, 2, 30, 5, 456 };
+	//cout << "numbers size/capacity: " << numbers.size() << " / " << numbers.capacity() << endl;
+	//numbers.push_back(999);
+	//cout << "numbers size/capacity: " << numbers.size() << " / " << numbers.capacity() << endl;
+	//numbers[3] = 67;
+	//
+	//list<int> numbers2 = { 0, 1, 2, 30, 5, 456 };
+	//list<int>::iterator it = numbers2.begin();
+	//for (; it != numbers2.end(); it++)
+	//{
+	//	//*it *= 2;
+	//	cout << *it << " ";
+	//}
+	//cout << endl;
+
+	//numbers2.insert(--it, 999);
+
+	//for (it = numbers2.begin(); it != numbers2.end(); it++)
+	//{
+	//	//*it *= 2;
+	//	cout << *it << " ";
+	//}
+	//cout << endl;
+
+	const size_t count = 5;
+	int numbers[count]; // const size -> stack array
+
+	size_t count2 = 10;
+	int* numbers2 = new int[count2]; // dynamic size -> heap array
+	delete[] numbers2;
+	numbers2 = nullptr;
 
 	return 0;
 }