Array Usage

Because automatic array indexing is a compile-time operation, it applies only when the resulting field is an array declared using the DIM keyword, and does NOT apply when resulting fields are arrays that use the RANK keyword. This is particularly important on assignments of the form array1 = <some expression>.

  • If array1 is a DIM-declared array, then the assignment expression WILL be indexed and follow the RPG rules (shorter array, etc). Any RANK-declared array in the expression will participate in indexing, and the user must be sure that the rank array contains sufficient elements, or a run-time error will occur.
  • If array1 is a RANK -declared array, then no automatic indexing will take place in expressions that have arrays as operands. i.e. myArr1 = myArr2 * myArr3.

If you want to use arrays in expressions, then those arrays must be RPG arrays (DIM arrays).

For the commands that operate on arrays, the array in the RESULT field must be a DIM array.

Examples

// Example 1 dimArray1 = dimArray2 + rankArray1 becomes…

 DO 0 <shorter length of dimArray1 and dimArray2 minus 1> Index
  dimArray1[ Index ] = dimArray2[ Index ] + rankArray1[ Index ]
 ENDDO

// remains the same, no code changes rankArray1 = dimArray1

// this generates a compiler error rankArray1 = dimArray1 + dimArray2

// Example 2 ZADD 3 dimArray1 becomes…

 DO 0 <length of dimArray1 minus 1> Index 
   ZADD 3 dimArray1[ Index ] 
 ENDDO

// This generates a compiler error ZADD 4 rankArray1

Array Overview

Language Concepts Main Topics

See Also

BEGFUNC

BEGPROP

DCLARRAY

DCLDSFLD

DCLOVERLAYGROUP

DCLSRPARM