PureBasic Forums - English

Originally posted by Pupil

why not use pointers in your structure to another structure, something like this:

Code: Select all

structure StreetType
  name.s
  nr.w
  *parent
  *child
endstructure

structure DataBaseType
  name.s
  etc.l
  *street
endstructure

newlist streets.StreetType()
newlist database.DataBaseType()

; ok now add an entry
addelement(database())
addelement(streets())
database()\name = "Vain"
database()\street = @streets()
*ptr.StreetType = @streets()
street()\name = "somewhere"
; he lives on another address too so..
addelement(street())
street()\name = "somewhere else"
*ptr\child = @street()

; now you can access this structure like this
resetlist(database())
while nextelement(database())
  *ptr = database()\*street
  if *ptr ; we have a street
    debug *ptr\name
    while *ptr\child
      *ptr = *ptr\child
      debug *ptr\name
    wend
  endif
wend

well something like that, i haven't tested because i'm at work at the moment, but the logic should be ok...

Originally posted by Pupil

>Pupil, I get an error "A variable in a structure needs a declared
>type"??? I'd love to learn more about the way you think, pointer
>stuff I know nothing about, need a guru to refer to

This was quite some time ago, what was i thinking? -beats me
You could probably get the example to work by inserting .l after the *pointer(in structure) variables, but i discovered (when using this technique in an actual application) that droping the '*' characters makes the source more readable (at least i think it does):
'var1\*child'
versus
'var1\child'

so change the structures to something like this:

Code: Select all

Structure ExampleStruct
  name.s
  var1.l
  child.l ; pointer to a child object
  parent.l ; pointer to a parent object
EndStructure

The way i'm doing things here is just mimicing how the LinkedList library works and how Linked lists work in general.

If something is unclear please say so and i'll try to explain it a little better...