diff --git a/practice_12/CMakeLists.txt b/practice_12/CMakeLists.txt
new file mode 100644
index 0000000..76fa8cf
--- /dev/null
+++ b/practice_12/CMakeLists.txt
@@ -0,0 +1,9 @@
+cmake_minimum_required(VERSION 3.0)
+project(practice_12)
+
+add_compile_options(-g -Wall -std=c++17)
+
+include_directories(include)
+
+add_executable(main main.cpp)
+
diff --git a/practice_12/build.sh b/practice_12/build.sh
new file mode 100755
index 0000000..10c5860
--- /dev/null
+++ b/practice_12/build.sh
@@ -0,0 +1,10 @@
+#!/bin/bash
+if ! [ -d build ]; then
+    echo "Creating build directory..."
+    mkdir build
+fi
+
+cd build
+cmake ..
+make
+exit
diff --git a/practice_12/include/FancySafeArray.hpp b/practice_12/include/FancySafeArray.hpp
new file mode 100644
index 0000000..7c7c222
--- /dev/null
+++ b/practice_12/include/FancySafeArray.hpp
@@ -0,0 +1,37 @@
+#ifndef FANCY_HPP
+#define FANCY_HPP
+
+#include <iostream>
+#include <SafeArray.hpp>
+
+template<class T>
+class FancySafeArray: public SafeArray {
+    public:
+        FancySafeArray(size_t size): SafeArray(size) { };
+        FancySafeArray(const FancySafeArray<T>& ar): SafeArray(ar) { };
+
+        FancySafeArray operator+(const FancySafeArray& rhs) const {
+            size_t new_size = size_ + rhs.size;
+            FancySafeArray new_array(new_size);
+            for (size_t i = 0; i < size_; ++i) {
+                new_array[i] = data[i];
+            }
+            for (size_t i = size_; i < rhs.size; ++i) {
+                new_array[i] = rhs[i];
+            }
+            return new_array;
+        }
+};
+
+template<class T>
+std::ostream& operator<<(std::ostream& os, const FancySafeArray& fsa) {
+    os << "[";
+    for (size_t i = 0; i < fsa.getSize(); ++i) {
+        os << fsa[i];
+        if(!i%5) os << std::endl;
+    }
+    os << "]" << std::endl;
+    return os;
+}
+
+#endif
diff --git a/practice_12/include/SafeArray.hpp b/practice_12/include/SafeArray.hpp
new file mode 100644
index 0000000..76ae3f7
--- /dev/null
+++ b/practice_12/include/SafeArray.hpp
@@ -0,0 +1,77 @@
+#ifndef SAFE_ARRAY_HPP
+#define SAFE_ARRAY_HPP
+
+#include <memory>
+#include <iostream>
+#include <exception>
+
+template<class T>
+class SafeArray {
+    public:
+        SafeArray(): size_(0) { }
+
+        SafeArray(unsigned int size):
+        size_(size)    
+        {
+            data = std::make_unique<T[]>(size_);
+        }
+        
+        SafeArray(const SafeArray<T>& ar):
+        size_(0)
+        {
+            size_ = ar.size();
+            data.reset(new T[size_]);
+            for(unsigned int i = 0; i < size_; ++i) {
+                data[i] = ar[i];
+            }
+        }
+
+        SafeArray<T>& operator=(const SafeArray<T>& ar) {
+            size_ = ar.size();
+            std::unique_ptr<T[]> temp = std::move(data);
+            data.reset(new T[size_]);
+            for(unsigned int i = 0; i < size_; ++i) {
+                data[i] = ar[i];
+            }
+            return *this;
+        }
+
+        void insert(const T& value, size_t index) {
+            if(size_ < index) throw 
+            data[index] = value;
+        }
+
+        void resize(size_t new_size) {
+            std::unique_ptr<T[]> temp(new T[new_size]{});
+            for(size_t i = 0; i < new_size; ++i) {
+                if(i >= size_) {
+                    break;
+                }
+                temp[i] = data[i];
+            }
+            std::swap(temp, data);
+            size_ = new_size;
+        }
+
+        T* begin(void) { return data.get(); }
+        T* end(void) { return &data[size_]; };
+        
+        size_t size(void) const { return size_; }
+
+        T& operator[](size_t index){
+            if (index > size_) throw std::out_of_range;
+            return data[index];
+        }
+
+        const T& operator[](size_t index) const {
+            if (index > size_) throw std::out_of_range;
+            return data[index];
+        }
+    
+    private:
+        unsigned int size_;
+        std::unique_ptr<T[]> data;
+};
+
+#endif
+
diff --git a/practice_12/main.cpp b/practice_12/main.cpp
new file mode 100644
index 0000000..053d3cc
--- /dev/null
+++ b/practice_12/main.cpp
@@ -0,0 +1,44 @@
+#include <SafeArray.hpp>
+#include <iostream>
+#include <string>
+
+int main(void) {
+    SafeArray<int> array(10);
+    for(size_t i = 0; i < 10; ++i) {
+        array[i] = i * i;
+    }
+
+    std::cout << "Array 1:" << std::endl;
+    for(int x: array) {
+        std::cout << x << std::endl;
+    }
+
+    SafeArray<int> array2(array);
+    array2.resize(5);
+    
+    std::cout << array2[7];
+    std::cout << "Array 2:" << std::endl; 
+    for(int x: array2) {
+        std::cout << x << std::endl;
+    }
+    
+    SafeArray<int> array3 = array2;
+    array3.resize(10);
+    std::cout << "Array 3:" << std::endl;
+    for(int x: array3) {
+        std::cout << x << std::endl;
+    }
+    
+    SafeArray<std::string> string_array(10);
+    for(size_t i = 0; i < 10; ++i) {
+        string_array[i] = "The number: " + std::to_string(i);
+    }
+    
+    std::cout << "String array:" << std::endl;
+    for(std::string s: string_array) {
+        std::cout << s << std::endl;
+    }
+
+    SafeArray<std::string> new_string_array(string_array);
+    return 0;
+}