how do you make comparison between vectors?

[nethz13]

code i try is like

if (getVelocity() [COLOR="Red"]equals (20.0, 0.0))[/COLOR]{
        setBodyImage(new BodyImage("st1mob2walkR.gif"));

i am not sure about the red bit,
however I used system println for getVelocity(), which shows on the terminal are vectors (20.0,0.0)[I also check the doc.]
what should I do to make the red bit working as I was intended?

[Fubarable]

The Vector (or better its parent, AbstractList) API has important information about the equals method that is pertinent here. But having said that, the amateur physicist in me makes me think that this Vector holds velocity information, and that you'll want to set your body image to a "walking(?)" image if the speed is > something and < something else. If so then your approach will need to change.

[nethz13]

The Vector (or better its parent, AbstractList) API has important information about the equals method that is pertinent here. But having said that, the amateur physicist in me makes me think that this Vector holds velocity information, and that you'll want to set your body image to a "walking(?)" image if the speed is > something and < something else. If so then your approach will need to change.

yes.. but >something or <something does not apply on getVelocity()
and getVelocity() is the only good way I have, to determent the monster is walking left or right..
but just in short, the info like (20.0,0.0) is comparable or not?

[Fubarable]

but just in short, the info like (20.0,0.0) is comparable or not?

In short, yes it is. You may use the equals method, but I'd advise you read the section on it in the AbstractList API.

[nethz13]

In short, yes it is. You may use the equals method, but I'd advise you read the section on it in the AbstractList API.

I must having something seriously wrong here..
I tried getVelocity().equals(0.0) which the code will compile but its velocity is change to 0.0 when I touch it..

[Fubarable]

You can't compare a Vector to a double but rather only to another Vector. In fact that's one of the basic rules when using the equals method: you can only compare one object with another object of the same class.

[nethz13]

You can't compare a Vector to a double but rather only to another Vector. In fact that's one of the basic rules when using the equals method: you can only compare one object with another object of the same class.

yes, that is what i read from the book as well. does it mean I have no way to make some number and use equals to compare with it?
and if equals is not good, any more suggestions? Thanks..

[Fubarable]

yes, that is what i read from the book as well. does it mean I have no way to make some number and use equals to compare with it?
and if equals is not good, any more suggestions? Thanks..

Who said equals is "not good"? You need to compare one Vector with another Vector, that's all.

[Cruncher]

do those doubles exist in the constructor?

i don't know this class specifically but wouldn't something like

vector1.equals(new Vector(double1, double2));

work

??

yeah uhm, i just looked at the api for vector and it's kind of strange, suggest you do what fub suggested, read that api front and back, and the class it extends from.