Are constructors only useful to call private members of a class?

[SomeAmazingGuy]

The title is pretty much self-explanatory. Are there any other uses for constructors?

[Ganado]

Initialize data members? That's probably the most important part. (Whether they're private or not)

Edit:
Also if dynamic allocation is needed, it's usually done in the constructor, and then deleted in the destructor.

[SomeAmazingGuy]

Ok just making sure