What internal mechanisms are behind the implementation of an in-memory array?

An array in memory is implemented as a contiguous block of memory where elements are stored sequentially. This allows for quick access to elements by index, calculating the address as the base address + (index * size of element). This approach ensures efficient cache usage and fast addressing.

For example, in Swift, arrays are stored on the heap, and a variable holds a reference to this block. When adding elements, memory may be reallocated if the current block is full.

var numbers = [1, 2, 3]
numbers.append(4) // A new memory block is allocated if necessary