C++ (Vectors & Arrays) (doubles & floats)?

Question

Why would we use arrays than vectors? Aren't vectors better to use, and is more useful?

What about doubles, and floats? Why would we need floats, only accurate at 6 digits after the decimal then doubles, about 16 accurate digits after the decimal?

Can someone explain?

Answer 1

In general I would use vectors and doubles. Arrays can be used to avoid heap allocations since they can be allocated on the stack. Floats use half the memory, so they provide a trade-off between precision and space.

Answer 2

I see, thanks.