Let's test this container to ensure that each constructor works as expected:

int main(void)
{
    auto alloc = std::allocator<int>();

    container<int> c1;
    container<int> c2(alloc);
    container<int> c3(42, 42);
    container<int> c4(42);
    container<int> c5(c1, alloc);
    container<int> c6(std::move(c1));
    container<int> c7(std::move(c2), alloc);
    container<int> c8{4, 42, 15, 8, 23, 16};

    return 0;
}

As shown in the preceding code block, we test our constructors by calling each one, which results in the following output:

As you can see, each constructor was successfully executed as expected.