How are the elements of an array of class objects arranged in memory?

Question

C++ / C#

How are arrays of class objects arranged? In theory, moving through the array occurs when the pointer is shifted by a certain number of bytes, but a class object can contain both a vector and a template can be, which means that different elements of the array (class objects) can occupy a different number of bytes in memory. How is this problem solved in c++?

Answer 1

Objects in C++ have a constant size, known at compile time, equal to sizeof( instance )
Statement:

a class object can also contain a vector ... which means that different array elements (class objects) can occupy a different number of bytes in memory.

incorrect , since the vector does not store its data in its instance, but where the allocator puts it (usually puts it on the heap).
Statement:

[class object] and template can be ... which means that different array elements (class objects) can occupy a different number of bytes in memory.

false , since all templates are instantiated at compile time.
Consequently, class objects sit in an array one after another, have a fixed size, and you can crawl over them with a pointer, shifting it by this size.