Dynamic Arrays

A dynamic array is just like an array except that the size is not static. A dynamic array can grow and shrink to meet your needs while the program is running.

How Do Dynamic Arrays Change Size

The underlying structure of a dynamic array is a regular array. To make it dynamic we need to do some extra book keeping. We need to store a count, which is the number of elements in the array. We also need to store the capacity, which is the size of the underlying array. When someone inserts into the array, we add the element at the end of the list, but if the array is full, then we create a new larger array and copy all the values from the original array into the new one. This can be an expensive operation, but since the operation is rare, it is still very performant.