Creating C++ objects

Question

I noticed that there are two ways to create C++ objects:

BTree *btree = new BTree;

and

BTree btree;

From what I can tell, the only difference is in how class objects are accessed (. vs. -> operator), and when the first way is used, private integers get initialized to 0.

Which way is better, and what's the difference?

How do you know when to use one or the other?

Answer 1

Two differences:

• they create the objects in different parts of the memory (heap vs stack)

• the object lifetime is different: In the first case, the code manages the memory allocation explicitly, and it must also manage the deallocation explicitly (using delete/delete[]).

  In the second case, the object is automatically deallocated at the end of its enclosing scope (either a method, a nested block within a method, or a class)

Which one you uses depends mostly on the lifetime of the object (if it should outlive the method in which it is created or not).