void left(char* s)
{
    s[0] = '0';
    for (size_t i = 0; s[i + 1] != '\0'; ++i)
    {
        swap(s[i], s[i + 1]);
    }
}

void right(char* s)
{
    size_t size;
    for (size = 0; s[size] != '\0'; ++size);
    s[size - 1] = '0';
    for (size_t i = size - 1; i > 0; --i)
    {
        swap(s[i], s[i - 1]);
    }
}

char* addition(const char* left, const char* right)
{
    size_t leftSize, rightSize;
    for (leftSize = 0; left[leftSize] != '\0'; ++leftSize);
    for (rightSize = 0; right[rightSize] != '\0'; ++rightSize);
    size_t length = std::max(leftSize, rightSize);
    char* res = new char[length + 1];
    res[length] = '\0';

    size_t i = 1;
    for (i = 1; leftSize >= i && rightSize >= i; ++i)
    {
        res[length - i] = (left[leftSize - i] == '1' || right[rightSize - i] == '1' ? '1' : '0');
    }
    for (; leftSize >= i; ++i)
    {
        res[length - i] = left[leftSize - i];
    }
    for (; rightSize >= i; ++i)
    {
        res[length - i] = right[rightSize - i];
    }
    return res;
}

char* composition(const char* left, const char* right)
{
    size_t leftSize, rightSize;
    for (leftSize = 0; left[leftSize] != '\0'; ++leftSize);
    for (rightSize = 0; right[rightSize] != '\0'; ++rightSize);
    size_t length = std::max(leftSize, rightSize);
    char* res = new char[length + 1];
    res[length] = '\0';

    size_t i = 1;
    for (i = 1; leftSize >= i && rightSize >= i; ++i)
    {
        res[length - i] = (left[leftSize - i] == '1' && right[rightSize - i] == '1' ? '1' : '0');
    }
    for (; length >= i; ++i)
    {
        res[length - i] = '0';
    }
    return res;
}

char* hex(const char* s)
{
    size_t size;
    for (size = 0; s[size] != '\0'; ++size);
    size_t length = (size + 3) / 4;
    char* res = new char[length + 1];
    res[length] = '\0';

    char* ptr = res;
    int add = (size % 4 > 0 ? size % 4 : 4);
    for (int i = 0; i < size; i += add)
    {
        size_t base = 1;
        int dig = 0;
        for (int j = i + add - 1; j >= i; --j)
        {
            dig += (s[j] == '1') * base;
            base *= 2;
        }
        *ptr++ = "0123456789ABCDEF"[dig];
        add = 4;
    }
    return res;
}