C++ Basics: Object Instantiation vs. Dynamic Memory Allocation

[WittyFool]

Quick question while learning C++:

Say you have class A, you can instantiate an object of class A like:

A a;

And then you can do stuff with that class (eg, a.method(), etc.)

But you can also do:

A a = new A();

And do stuff with that, and delete it with:

delete a;

My question: What's the difference between the two?

[Narue]

>What's the difference between the two?
The difference is how you access the object, how long the object lives, and where it's stored.

[kon_t]

Your code wont compile as is. What you need to have is

void aFunction
{
       A   a;        // create local auto object on the stack

       A* ap = new A()  // create object on the heap & have ap refer to it

       // do something

      delete ap;      // manually delete object that ap refers to
}   // here a & ap are destroyed automatically