Can I read a single value from an array?

Okay, so I've got this array:

WayPointList:Int[1536,2560,1,0,0,0]

It's supposed to be a list of waypoints and the speed at which the screen should scroll from the old waypoint to the next one. I.E. this format:

[x,y,speed,x,y,speed... etc.]

Now I'm trying to figure out how arrays work in Blitz. This documentation is terrible. It explains how to use EachIn to loop through an entire array, but what's the command to just read one element from the array?

In other words, how would I go about doing:

camera.x = (first item from the array WayPointList)
camera.y = (second item from the array WayPointList)
camera.speed = (third item from the array WayPointList)

Also, are these arrays one-based or zero-based? (I.E. Is the first item in the array refered to by the number 0 or 1?)

Thanks.

To read a specific element in an array, use the numeric index. For example, WayPointList[0] would return 1536, WayPointList[1] would return 2560, and so on.

Hmmm. That's the first thing I tried, but it gave me a compiler error:

"Compile Error: Incorrect number of array dimensions"

Since the array keyword in the blitzmax help file doesn't explain the array-related compiler errors or all of the array functionality, I have no idea how to interpret this.

I guess flash's documentation has just spoiled me. I'm too used to being able to F1 a keyword and getting a cross-referenced hyperlinked dictionary for my efforts. :P

EDIT: Oh, wait... I think the problem is my array constructor.

WayPointList:Int[1536,2560,1,0,0,0]

That's not right. That creates a multidimensional array, doesn't it? :P I wanted a single-dimmensional array with those explicit values.

Edit again: I found it in the help I badmouthed earlier. :P For those of you who might have the same problem...

Global WayPointList:Int[]=[1536,2560,1,0,0,0] 

..is apparently the correct way to do it.

Thanks, guys. :) Sorry for bothreing you.

ok right off Global WayPointList:Int[]=[1536,2560,1,0,0,0]
makes no sence

What are you trying to do?

Make a TYPE with all the (int) fields you want, THEN, make an array of that type.

type whatever
field xcoor:int
Field ycoor:int
Field speed:int etc
EndType

On the 0 or one thing, they start at 1 when defining them, and at 0 when accessing them

Shouldn't it be:

Global WayPointList:Int[]=[1536,2560,1,0,0,0]

and

Print WayPointList[0] 'Print first x value

WayPointList:Int[1536,2560,1,0,0,0]

This creates an array of 1536 x 2560 x 1 items!

try:

WayPointList:Int[] = [1536, 2560, 1, 0, 0, 0]

*edit*

that's what I get for playing naked war before answering :)

@Angel

It still makes no sence
Global WayPointList:Int[]=[1536,2560,2,1,1,1]

Edit. Have I made a realy stupid mistake here?

Was the rhetorical? ;)

I dunno. Blitz help says Global WayPointList:Int[]=[1536,2560,2,1,1,1] should work.



It compiles. No crashes. No errors. Go figure.

yes, it's fine.

see http://www.blitzwiki.org/index.php/Arrays#Auto_Arrays

Even if I am wrong about that ;) I still think;

You should definitaly make a type for all of the fields you want in ANY single dimention array. And make an array of that type.

what? even for an array of ints?

Yes. If its a single dimention array of TWO ints, then yes

I dont do array:Int[NumberofIntPairs,2]
i do Array:BiIntPair[NumberOfIntPairs]

make an array of types.

On how to create it:

global waypoints:Int[2*NumberOfIntPaires]

And use it:

x = waypoint[indexOfTheWayPoint*2]
y = waypoint[indexOfTheWaypoint*2 + 1]

BlitzMax arrays are zero based (0 to length-1)

Btw: Filling arrays with [value,value,value] is a bad idea if you plan to use it realtime, beause this is extremely slow, compared to create it with new and fill it manually!

Okay, I finally managed to find an example of this "array of types" technique, but it's in B3D.

Type Test
 field x, y
end type

Dim MyType.Test( 100 )

For l = 0 to 100
  MyType(l)  = new Test
  MyType(l)\x = rand(10)
  MyType(l)\y = rand(10)
next

How do convert this to BMX?

(Sorry for asking stupid questions, but I've never done this before and the documentation is no help.)

Arrays in Blitzmax are not 1 element more.

Type Test
 Field x, y
End Type

Global MyType:Test[101] 

For l = 0 To 100
  MyType[l]  = New Test
  MyType[l].x = Rand(10)
  MyType[i].y = Rand(10)
Next