Array and data structure processing.

[ChrisL]

Hi everyone,

I'm having a moment and wondered if someone could point me the right way.

I've got a screen which will allow me to create adjustments to an order, these (once confirmed) will eventually post into a file, but I don't want to post them to a file until the users confirms.

So I though I could create an array with a data structure mapped over it to hold me field level data.

d adjArray        ds                  qualified dim(1000)
d item                                like(Item#)
d OrgQty                              like(OrdQty)
d NewQty                              like(OrdQty)
d Reference                           like(OrdRef)

So I plan to build this array with data entered from the screen, if a user tries to enter something for an item already entered I want to retrieve the values from my array / data structure.

My issue is retrieving from my array based only on item number?

Will this work, if so how do I go about checking for existence of my item, if not, what is the best way of going about it?

[ChrisL]

Re: Array and data structure processing.

I've gotten around my issue by looping through all elements in my array and looking where adjArray(x).Item = dspItem, although I can't help but think that there must be a better way to do this?

[TedHolt]

Re: Array and data structure processing.

I've been working on a program with a similar requirement recently. I wrote my own lookup routine for the array.

I have a variable that keeps up with how many elements have been loaded. Each time, I add an element to the array, I increment that variable. So my loop starts with the last element loaded and searches backwards thru the array. I end the loop when I find a match or the loop control variable gets to zero, whichever comes first.

I don't have the RPG code at hand, but the pseudocode would be something like this:

loop-control = Number of elements that have been loaded

dow loop-control > zero 
and array.item [loop-control] <> SearchItem
   loop-control = loop-control - 1
end dow

// if loop-control is zero, the search item is not in the array

It may not be the best solution, but it's working and I'm not touching it.

[ChrisL]

Re: Array and data structure processing.

Thanks Ted,

That's almost exactly what I've done, in the example below "x" holds the total loaded elements in my array..

y= 1;
dow y <= x;
  if adjArray(y).item = dspItem;
    // do processing here;
  endif;
  y += 1;
enddo;

[Brian Rusch]

Re: Array and data structure processing.

Unless I'm misunderstanding the manual and/or the requirement, wouldn't this work:

index = %lookup(dspItem:adjArray(*).item:1:x);
If index > 0;
// array entry found
Else;
// array entry not found
Endif;

[ChrisL]

Re: Array and data structure processing.

hi Brian,

I did try that originally and get compile errors "*RNF0571 The second parameter for %LOOKUPxx is not valid."

*edit* should point out I'm on V5R4

[Scott M]

Re: Array and data structure processing.

The ability to search like Brian showed was added in V7R1

[RayGilliesJones]

Re: Array and data structure processing.

I guess it depends on how big you think the array might get. If it's going to get huge (and I'm guessing that it isn't) there might be a more efficient way of arranging the structure, but for only a handful of entries it would be overkill to do anything other than a linear search.

[ChrisL]

Re: Array and data structure processing.

Thanks Scott and Ray,

I've only got 1,000 elements in my array, you're right I don't think they will notice the extra processing time needed, I'd just hoped for a cleaner coding solution, which as Scott says is available at a later release

[RayGilliesJones]

Re: Array and data structure processing.

I'd just hoped for a cleaner coding solution, which as Scott says is available at a later release

Tell me about it - we are stuck on V5R4 ... and are very unlikely to move to anything else.

[Brian Rusch]

Re: Array and data structure processing.

V5R4, gotcha. How about this, then:

d adjDs           ds                  
d  adjArray                    100    dim(1000)
d   item                              like(Item#) overlay(adjArray)
d   OrgQty                            like(OrdQty) overlay(adjArray:*next)
d   NewQty                            like(OrdQty) overlay(adjArray:*next)
d   Reference                         like(OrdRef) overlay(adjArray:*next)

index = %lookup(dspItem:item:1:x);
If index > 0;
// array entry found
Else;
// array entry not found
Endif;

Note: I just guessed at the length of adjArray as 100, replace it with the actual length. Also, I took out the QUALIFIED keyword as I'm not sure it will work with this technique, but it might.

[Scott Klement]

Re: Array and data structure processing.

Te %LOOKUP (like Brian's first post) should work if you're on 7.1

For earlier releases, a simple loop shoudl work fine.

  for x = 1 to %elem(adjArray);
    if adjArray(x).item = ThingToSearchFor;
        found = x;
        leave;
    endif;
endfor;

I can't see why you'd convert this to an overlay array, which is extremely ugly and cumbersome to deal with. A loop just isn't that hard to write.

[avoronyuk13]

Re: Array and data structure processing.

Try something like this.

d @item S dim(%elem(adjArray)) like(Item#)

@item = adjArray;
if %lookup(dspItem:@item) >*zero;