RE: pointers

[Buck Calabro <buck.calabro@xxxxxxxxxxxxxxxxx>]

James Rich wrote:

>basically I want a 2-dimensional array that I 
>can dynamically increase or decrease.

Jon Paris submitted this a while ago (see the Redbook for more fun with
pointers)  It should server as a starting point.  Any errors are due to my
changes:

PDYNARRAY         b                                                   
DDYNARRAY         pi                                                  
 * Note: the value supplied to the DIM statement is used by RPG as    
 *       the maximum size that the array can grow to - since the array
 *       is being dynamically sized this is used as a "sanity check"  
 *       only. i.e. If it ever gets this big the program is looping !!
                                                                      
D Array           S                   Dim(20000) Based(Ptr) Like(NAME)
                                                                      
D CurrElems       S              3  0 Inz(50)                         
D RecordsRead     S              5  0 Inz                             
D Memory          S              7  0 Inz                             
                                                                      
 * Allocate initial storage                                           
C                   Eval      Memory = %Size(Array) * CurrElems       
C                   Alloc     Memory        Ptr                       
                                                                      
 * Loop reading file and storing records in array                     
C                   DoU       %EOF(Master)                            
C                   Read      Master                                  
                                                                      
C                   If        Not %EOF(Master)                        
C                   Eval      RecordsRead = RecordsRead + 1           
                                                                      
 * Limit this example to 200 records                                  
C                   If        RecordsRead > 200                       
C                   Leave                                             
C                   EndIf                                             
                                                                      
 * Need more space - increase by 20 & reallocate                      
C                   If        RecordsRead > CurrElems                 
C                   Eval      CurrElems = CurrElems + 20              
C                   Eval      Memory = %Size(Array) * CurrElems       
C                   REALLOC   Memory        Ptr                    20 
C                   EndIf                                             
                                                                      
C                   Eval      Array(RecordsRead) = NAME               
                                                                      
C                   EndIf                                             
C                   EndDo                                             
                                                                      
 * Don't forget to free up array when no longer needed                
C                   DEALLOC                 Ptr
                                               
PDYNARRAY         e                            

Buck Calabro
Aptis; Albany, NY


Billing Concepts Corp., a NASDAQ Listed Company, Symbol: BILL
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