Purpose of Dynamic Classes?

[Shokwav]

Can you someone please expalin to me the purpose of dynamic classes? I know HOW to do it, but I don't know WHY to do it. Arrays I understand, as you usually need the size to be determined at runtime. However, why classes? If any variables inside need to be dynamic, I'll declare them as such. I just can't seem to grasp it...

[manasij7479]

What exactly do you mean by "Dynamic" Classes ?

As you "know how to do it", posting a small example would help.

[Shokwav]

A class... that's dynamic.

class foo{};
foo bar = new foo();

[std10093]

A class... that's dynamic.

class foo{};
foo bar = new foo();

You have to use the new keyword in order to create an instance of the object,call the constructor and allocate memory!By saying "Dynamic" Classes you might to be a little confused.

[manasij7479]

Unfortunately, the class is not 'dynamic' by any interpretation of the term 'dynamic'.
You are confusing a class and an object of that class.

Btw, new returns a pointer to a foo object .
So it'd be like:

foo* bar = new foo();

It is mainly useful because the object is created on the heap and is not lost like local variables at the end of scope.

[Shokwav]

Unfortunately, the class is not 'dynamic' by any interpretation of the term 'dynamic'.
You are confusing a class and an object of that class.

Yeah, I should have said dynamic objects, sorry.

Btw, new returns a pointer to a foo object .
So it'd be like:

foo* bar = new foo();

Derp, I forgot the *...

It is mainly useful because the object is created on the heap and is not lost like local variables at the end of scope.

This makes a lot of sense. I was wondering if there was any other deeper purpose, but this makes a lot of sense; thanks.

[manasij7479]

I was wondering if there was any other deeper purpose

There are a few, which you'll learn as soon as the issues start biting you. (Object Splicing in inheritance is the only one I can recall now.)

And of course the heap is many hundred times larger than the stacks.

[Elysia]

You have to use the new keyword in order to create an instance of the object,call the constructor and allocate memory!By saying "Dynamic" Classes you might to be a little confused.

Errr, they can be declared on the stack, too, and it will work just fine.

Btw, another use is when you have different parts of the program that needs to share the same object.