#include <iostream>
#include <cstring>

enum
{
    EXP_VALUE = 2
};



class String
{
    class Buffer;
    Buffer* buffer = nullptr;
public:
    String(const char* s = nullptr)
    {
        size_t len = strlen(s);
        if (len != 0)
        {

        }
    }
    String(const String& copy_string)
    {

    }
    ~String()
    {

    }

    String& operator= (const String& assign_string)
    {

    }

    String& operator+= (const String& concat_string)
    {

    }

    char& operator[] (const size_t index)
    {
        return buffer->get_index(index);
    }

    char operator[] (const size_t index) const
    {

    }
};

class String::Buffer
{
    void* owner_address = nullptr;
    char* data = nullptr;
    size_t length = 0;
    size_t capacity = 0;
    void make_correct_for_length(size_t required_length)
    {
        if (required_length >= capacity)
        {
            capacity = EXP_VALUE * capacity + 1;
            char* new_data = new char[capacity];
            for (size_t i = 0; i < length; i++)
            {
                new_data[i] = data[i];
            }
            delete[] data;
            data = new_data;
        }
    }
public:
    void add(const char* text, size_t len)
    {
        make_correct_for_length(length + len);
        for (size_t i = 0; i < len; i++)
        {
            data[length + i] = text[i];
        }
    }
    char& get_index(size_t index) const
    {
        return data[index];
    }
    Buffer() {};
    ~Buffer()
    {
        if (length != 0)
        {
            delete[] data;
        }
    }
};