Singleton vs Static.

[Quantum]

Hi,

What is the difference between a singleton class and a static class?
From what I can tell, they both offer the same functionality, i.e. only
one copy of a class.

Thanks,
Q

[Kirit Sælensminde]

Re: Singleton vs Static.


Quantum wrote:

Hi,
>
What is the difference between a singleton class and a static class?
From what I can tell, they both offer the same functionality, i.e. only
one copy of a class.
>
Thanks,
Q

You can have many statics of the the same, but only one singleton:

class A {
//...
};
class B {
static A a1;
static A a2;
static A a3;
static B &singleton() ;
};

There isn't really any such thing as a static class, there are static
members - either attributes or methods.

Have a think about the static members of type A in B and then have a
think about the singleton B. You'll see that they don't offer the same
functionality in this example, although it is certainly possible to use
them in such a way that they can.


K

[Earl Purple]

Re: Singleton vs Static.


Quantum wrote:

Hi,
>
What is the difference between a singleton class and a static class?
From what I can tell, they both offer the same functionality, i.e. only
one copy of a class.

A class with every member static is really a collection of functions
scoped by a class. Although you can use a namespace to do the same, the
purpose is usually to use the class as a template parameter (something
you can't do with a namespace).

std::char_trait s (template) is an example of such a class.

[Quantum]

Re: Singleton vs Static.

Earl Purple wrote:

Quantum wrote:

>Hi,
>>
>What is the difference between a singleton class and a static class?
> From what I can tell, they both offer the same functionality, i.e. only
>one copy of a class.

>
A class with every member static is really a collection of functions
scoped by a class. Although you can use a namespace to do the same, the
purpose is usually to use the class as a template parameter (something
you can't do with a namespace).
>
std::char_trait s (template) is an example of such a class.
>

Thank you both for your time. That's quite helpful. :)

Q