diff --git a/cpp/.idea/.name b/cpp/.idea/.name
index d366d2e..70a1f63 100644
--- a/cpp/.idea/.name
+++ b/cpp/.idea/.name
@@ -1 +1 @@
-classes
\ No newline at end of file
+containers
\ No newline at end of file
diff --git a/cpp/.idea/misc.xml b/cpp/.idea/misc.xml
index 7a865bb..cb02c5a 100644
--- a/cpp/.idea/misc.xml
+++ b/cpp/.idea/misc.xml
@@ -3,7 +3,7 @@
   <component name="CMakePythonSetting">
     <option name="pythonIntegrationState" value="YES" />
   </component>
-  <component name="CMakeWorkspace" PROJECT_DIR="$PROJECT_DIR$/classes">
+  <component name="CMakeWorkspace" PROJECT_DIR="$PROJECT_DIR$/containers">
     <contentRoot DIR="$PROJECT_DIR$" />
   </component>
 </project>
\ No newline at end of file
diff --git a/cpp/classes/ClassA.cpp b/cpp/classes/ClassA.cpp
index 1a156d4..09ac5be 100644
--- a/cpp/classes/ClassA.cpp
+++ b/cpp/classes/ClassA.cpp
@@ -2,6 +2,36 @@
 
 #include <iostream>
 
+ClassA::ClassA() : IComparable(), _number(0), _pDecimal(new float(0.0f))
+{
+    std::cout << "ClassA created" << std::endl;
+
+    // _pDecimal = new float(0.0f);
+}
+
+ClassA::ClassA(const ClassA &other) :
+    IComparable(other),
+    _number(other._number),
+    _pDecimal(new float(*other._pDecimal))
+{
+    std::cout << "ClassA copy created" << std::endl;
+
+    // shallow copy
+    // _number = other._number;
+    // _pDecimal = other._pDecimal;
+
+    // deep copy
+    // _number = other._number;
+    // _pDecimal = new float(*other._pDecimal);
+}
+
+ClassA::~ClassA() {
+    std::cout << "ClassA destroyed" << std::endl;
+
+    delete _pDecimal;
+    _pDecimal = nullptr;
+}
+
 void ClassA::Print()
 {
     std::cout << "ClassA" << std::endl;
diff --git a/cpp/classes/ClassA.h b/cpp/classes/ClassA.h
index f80ce9b..91683f4 100644
--- a/cpp/classes/ClassA.h
+++ b/cpp/classes/ClassA.h
@@ -8,15 +8,23 @@ class ClassA : public IComparable {
 
 public:
     // public
+    ClassA(); // default constructor
+    ClassA(const ClassA& other); // copy constructor
+    ~ClassA() override; // destructor
+
     void Print();
     int CompareTo(IComparable* other) override;
 
+    const float& GetDecimal() const { return *_pDecimal; }
+    void SetDecimal(float decimal) { *_pDecimal = decimal; }
+
 protected:
     // protected
 
 private:
     // private
     int _number = 0;
+    float* _pDecimal = nullptr;
 };
 
 
diff --git a/cpp/classes/IComparable.h b/cpp/classes/IComparable.h
index 904dd2f..48806d1 100644
--- a/cpp/classes/IComparable.h
+++ b/cpp/classes/IComparable.h
@@ -1,8 +1,13 @@
 #ifndef CLASSES_ICOMPARABLE_H
 #define CLASSES_ICOMPARABLE_H
+#include <iostream>
 
 class IComparable {
 public:
+    // only for presentation purpose
+    IComparable() { std::cout << "IComparable created" << std::endl; }
+    virtual ~IComparable() { std::cout << "IComparable destroyed" << std::endl; }
+
     virtual int CompareTo(IComparable* other) = 0;
 };
 
diff --git a/cpp/classes/main.cpp b/cpp/classes/main.cpp
index 8033109..ead7640 100644
--- a/cpp/classes/main.cpp
+++ b/cpp/classes/main.cpp
@@ -13,5 +13,18 @@ int main() {
 
     a.CompareTo(pA);
 
+    IComparable* pComparable = nullptr;
+    pComparable = new ClassA();
+    pComparable->CompareTo(&a);
+    // pA = dynamic_cast<ClassA *>(pComparable);
+    // if (pA != nullptr) {
+    //     pA->Print();
+    // }
+    delete pComparable;
+    pComparable = nullptr;
+
+    ClassA a2 = a;
+
+
     return 0;
 }
\ No newline at end of file
diff --git a/cpp/containers/CMakeLists.txt b/cpp/containers/CMakeLists.txt
new file mode 100644
index 0000000..0b71bc0
--- /dev/null
+++ b/cpp/containers/CMakeLists.txt
@@ -0,0 +1,9 @@
+cmake_minimum_required(VERSION 4.1)
+project(containers)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_FLAGS -pedantic-errors)
+
+add_executable(containers
+        main.cpp
+        functions.cpp)
diff --git a/cpp/containers/functions.cpp b/cpp/containers/functions.cpp
new file mode 100644
index 0000000..35d70f9
--- /dev/null
+++ b/cpp/containers/functions.cpp
@@ -0,0 +1,16 @@
+#include "functions.h"
+
+#include <iostream>
+
+void printArrayAtPosition(int* array, int position) {
+    if (array == nullptr) {
+        return;
+    }
+
+    if (position < 0) {
+        return;
+    }
+
+    std::cout << "size of array: " << sizeof(array) << std::endl;
+    std::cout << array[position] << std::endl;
+}
diff --git a/cpp/containers/functions.h b/cpp/containers/functions.h
new file mode 100644
index 0000000..d3c1340
--- /dev/null
+++ b/cpp/containers/functions.h
@@ -0,0 +1,10 @@
+//
+// Created by David Hackbarth on 20.02.26.
+//
+
+#ifndef CONTAINERS_FUNCTIONS_H
+#define CONTAINERS_FUNCTIONS_H
+
+void printArrayAtPosition(int* array, int position);
+
+#endif //CONTAINERS_FUNCTIONS_H
diff --git a/cpp/containers/main.cpp b/cpp/containers/main.cpp
new file mode 100644
index 0000000..bbdfb98
--- /dev/null
+++ b/cpp/containers/main.cpp
@@ -0,0 +1,39 @@
+#include <iostream>
+#include <vector>
+
+#include "functions.h"
+
+int main(int argc, const char* argv[]) {
+    // C array
+    int numbers[5] = {1, 2, 3, 4, 5}; // stack array
+    const int count = 10;
+    int numbers2[count];
+
+    int count2 = 10;
+    int* numbers3 = new int[count2]; // heap array
+    delete[] numbers3;
+    numbers3 = nullptr;
+
+    // numbers[10] = 100;
+    std::cout << "size of numbers: " << sizeof(numbers) << std::endl;
+
+    printArrayAtPosition(numbers, 19);
+
+    // vector
+    std::vector<int> v = {1, 2, 3, 4, 5};
+
+    std::cout << "size of v: " << v.size() << "/" << v.capacity() << std::endl;
+
+    v.push_back(6);
+
+    std::cout << "size of v: " << v.size() << "/" << v.capacity() << std::endl;
+
+    // v[20] = 100;
+    printArrayAtPosition(v.data(), 2);
+
+    v.pop_back();
+
+    std::cout << "size of v: " << v.size() << "/" << v.capacity() << std::endl;
+
+    return 0;
+}