Question about classes, and which way is best

**Swarvy** · 04-03-2008

I was thinking about this earlier, and it seemed a little unusual. I was hoping that you guys may be able to give me an answer to it.

If a class is declared like so:

Code:

class functions{
public:
void function1();
};

functions Function;

Then in the main code, both of the following ways of calling function1() will work. Which one is the best way of doing it, and what is the advantage(s) of doing that way? And why do we declare an object instance if it isn't essential?

Code:

int main()
{
// Lots of previous code
functions::function1();
// Some more code
}

Code:

int main()
{
// Lots of previous code
Function.function1();
// Some more code
}

**matsp** · 04-03-2008

The first of your main() samples will only work if function1 is a static function. This also means that there is no "this" pointer, and there is no need for an object. This is useful for special cases, such as when you just want a bunch of functions, but you have no data inside the class.

In most cases, you want the second version, which automatically passes the object to the function, and you can easily get to the functions member variables and functions.

--
Mats

**Elysia** · 04-03-2008

Originally Posted by Swarvy

Code:

int main()
{
// Lots of previous code
functions::function1();
// Some more code
}

With your current class definition, this doesn't work. This only works on static class members.

Code:

int main()
{
// Lots of previous code
Function.function1();
// Some more code
}

This is the real way of calling a class method.

**Swarvy** · 04-03-2008

cheers guys. That makes alot of sense. I'm glad you've clarified that.

**matsp** · 04-03-2008

And just to clarify - one isn't "better" than the other, just like a bin lorry isn't better than a fire-engine - they just serve different purposes.

--
Mats

**Dino** · 04-03-2008

lol. Not too many "bin lorries" on this side of the pond. And NONE in Texas!

**matsp** · 04-03-2008

Originally Posted by Todd Burch

lol. Not too many "bin lorries" on this side of the pond. And NONE in Texas!

No, suppose they are called refuse lorries - funny that both the US and England sort of speak the same language, yet the language is quite different in places. (There's quite a few web-sites about the difference between British English and US English).

--
Mats

**Dino** · 04-03-2008

"Garbage Truck"

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