could anyone explain this?

It means that the method may not modify any member data. This also means that the method can't call any member methods that aren't 'const'.

You can also call const functions without instantiating the class. For example:

Vector3 SomeVector = RotationMatrix::objectToInertial(SomeOtherVector);

With a non-const function, you have to first create a copy of the class:

RotationMatrix SomeMatrix;Vector3 SomeVector = SomeMatrix.objectToInertial(SomeOtherVector);

i didnt know that... so putting const at the end will make it behave kind of like it was static ?

There are some vague similarities between const and static, but they are not really that similar. Compare the details of const with static.

Quote:

You can also call const functions without instantiating the class. For example: Vector3 SomeVector = RotationMatrix::objectToInertial(SomeOtherVector); With a non-const function, you have to first create a copy of the class: RotationMatrix SomeMatrix; Vector3 SomeVector = SomeMatrix.objectToInertial(SomeOtherVector);

I've never heard of that. Are you sure you aren't referring to static? Once you think about it that really doesn't make any sense, because it is possible to access member variables. Here's what I mean:

class Test{    int i;public:    int getI() const    {        return i;    }};int i = Test::getI(); // what should this return if it were possible

that useful to know!thanks.

one more question.
can u use inline functions in a class, like so:

class blah
{
public:
...
...
inline int blah_blah();
}

whenever i've done it the compiler has a fit!

thanks again!

Quote:

Original post by bytecoder Quote: You can also call const functions without instantiating the class. For example: Vector3 SomeVector = RotationMatrix::objectToInertial(SomeOtherVector); With a non-const function, you have to first create a copy of the class: RotationMatrix SomeMatrix; Vector3 SomeVector = SomeMatrix.objectToInertial(SomeOtherVector); I've never heard of that. Are you sure you aren't referring to static? Once you think about it that really doesn't make any sense, because it is possible to access member variables. Here's what I mean: class Test{ int i;public: int getI() const { return i; }};int i = Test::getI(); // what should this return if it were possible

You are correct and ApochPiQ is incorrect.

Quote:

Original post by MagicScript You are correct and ApochPiQ is incorrect.

Yeah, you're right... that was a brain fart. Ignore me [wink]

wait.. i dont understand.. what WOULD happen in bytecoders example? i mean, if i is a member variable, and getI() is a const function, then you do

int i = Test::getI();

what happends? i mean, what is returned? since i is a member data, who owns that data? whos i is it?

Quote:

Original post by graveyard filla wait.. i dont understand.. what WOULD happen in bytecoders example? i mean, if i is a member variable, and getI() is a const function, then you do int i = Test::getI(); what happends? i mean, what is returned? since i is a member data, who owns that data? whos i is it?

You would get a compiler error, because getI is not a static membeber function, so it needs an object to be called, like this.

Test foo;int i = foo.getI();

The i that "belongs to" foo would be returned in this case.

ok, so Apoch was wrong when he said "You can also call const functions without instantiating the class. For example:

Vector3 SomeVector = RotationMatrix::objectToInertial(SomeOtherVector);

"

?? just got confused because MagicScript said he WAS right, but now your saying hes wrong...

Quote:

Original post by graveyard filla ok, so Apoch was wrong when he said "You can also call const functions without instantiating the class. For example: Vector3 SomeVector = RotationMatrix::objectToInertial(SomeOtherVector); " ?? just got confused because MagicScript said he WAS right, but now your saying hes wrong...

bytecoder was illustrating why what ApochPiQ said couldn't be right. He stopped short of actually confirming that his example failed to compile, so I indicated that he was in fact correct.

You can only call static methods without an object as static member methods don't have a this pointer so it's impossible for them to refer to non-static member variables which is why you can call them without an object of the class the function is contained in.

Moral of the story: if you post articles for people, be sure you read them first so you know what you're talking about [wink]