#include <algorithm>
#include <cstddef> // size_t
#include <cstring> // strlen, strcpy
#include <iostream>


struct String {

    String(const char *str = "")
    {
        _size = strlen(str);
        this->str = new char[_size + 1];
        strcpy(this->str, str);
    }

    String(size_t substr, const char *str = "") : String(str)
    {
        this->substr = substr;
    }

    size_t size() const
    {
        return _size;
    }

    String(const String &other)
    {
        str = new char[other.size() + 1];
        strcpy(str, other.str);
        _size = other.size();
    }

    ~String()
    {
        delete[] str;
    }

    void resize(size_t new_size)
    {
        str = resize_(str, new_size);
    }

    String operator[](size_t i) const
    {
        if (substr == 0)
            return String(i + 1, str + i);
        String tmp = String(0, str);
        tmp.resize(i - substr + 1);
        return tmp;
    }

    char at(size_t i) const
    {
        return str[i];
    }

private:
    char *resize_(const char *str, size_t new_size)
    {
        char * res = new char[new_size + 1];
        char *p = res;
        const char * q = str;
        for (size_t i = 0; i < _size && i < new_size; ++i)
        {
            *p = *q;
            p++;
            q++;
        }
        res[new_size] = '\x0';
        _size = new_size;
        delete[] str;
        return res;
    }

    size_t _size;
    char *str;
    size_t substr = 0;
};

int main()
{
    String s1 = String("hello");
    String s2 = s1[0][4];

    std::cout << s2.size() << std::endl;

    for (size_t i = 0; i < s2.size(); i++)
        std::cout << s2.at(i);
    std::cout << std::endl;

    system("PAUSE");

    return 0;
}