Question

I’m trying to decide which I should use.

The pros of pointers to structures that I can think off the top of my head.

• Less space wasted if you don’t use all elements of your array.
• Less overheard when swapping array elements

Any other pro’s/con’s for both sides?

Answer 1

There’s a few other differences in these approaches:

• The array-of-pointers approach reduces the overhead in resizing the array;
• The array-of-pointers approach gives you an “empty” / “unused” value (NULL). If this is semantically valid in your application, then this is an advantage (you don’t have to alter your struct itself to express this);
• The array-of-pointers approach allows multiple elements of the array to refer to the same struct rather than a copy. Again, this is only an advantage if this situation is semantically reasonable for your application;
• The array-of-structures approach provides more locality of reference (structs close together in the array are also close together in memory, which can be a performance advantage in some situations);
• For very large numbers of items, the array-of-structures approach requires a large contiguous block of memory, which may not be available if your process address space has become fragmented.