Construct a child class based on a type string

[bartoli]

Hey, i've a small design question, i hope there is an easy answer.

What's the cleanest way to construct (at run time) an object O that is a child of a parent class P, if the child's type depends on an ID loaded as text from a file before the construction?
What i am trying to do is to load a list of items all deriving from an abstract class with the same acccess methods. The type of each item being written in the file describing the list.

Thanks in advance