Can Array-based lists can never be empty?

Answer 1

It's either an array or it's a list, it cannot be both. However, an empty array is entirely possible:

std::vector<int> my_vector; // an empty array

my_vector.push_back(42); // an array of 1 element

my_vector.push_back(1); // an array of 2 elements

my_vector.clear(); // an empty array

An empty list is also possible:

std::list<int> my_list; // an empty list

my_list.push_back(42); // a list of 1 element

my_list.push_back(1); // a list of 2 elements

my_list.clear(); // an empty list

The same thing can be done in C:

int* my_array = nullptr; // an empty array

my_array = malloc (2*sizeof(int)); // an array of 2 elements

my_array[0] = 42;

my_array[1] = 1;

free my_array; // an empty array

my_array = 0;