The array-dimension-definition is
used in the statement DEFINE DATA
OBJECT and in the
variable-definition option
of DEFINE DATA LOCAL,
DEFINE DATA
INDEPENDENT, DEFINE
DATA CONTEXT, DEFINE
DATA OBJECT.It is also used in the
DEFINE FUNCTION
statement.
The array-dimension-definition
has the following syntax:
{bound[:bound]}, 3
|
This document covers the following topics:
With an
array-dimension-definition, you define
the lower and upper bound of a dimension in an array-definition.
You can define up to 3 dimensions for an array.
See also Arrays in the Programming Guide.
| Syntax Element | Description |
|---|---|
bound |
Lower/Upper Bound:
A bound can be one of the following:
If only one bound is specified, the value represents the upper bound and the lower bound is assumed to be 1. |
If at least one bound in at least one dimension of an array is specified
as extensible, that array is then called an
X-array (eXtensible array).
Only one bound (either upper or lower) may be extensible in any one dimension,
but not both. Multi-dimensional arrays may have a mixture of constant and
extensible bounds, for example: #a(1:100, 1:*).
Example:
DEFINE DATA LOCAL 1 #ARRAY1(I4/1:10) 1 #ARRAY2(I4/10) 1 #X-ARRAY3(I4/1:*) 1 #X-ARRAY4(I4/*,1:5) 1 #X-ARRAY5(I4/*:10) 1 #X-ARRAY6(I4/1:10,100:*,*:1000) END-DEFINE
In the following table you can see the bounds of the arrays in the above program more clearly.
| Dimension 1 | Dimension 2 | Dimension 3 | ||||
|---|---|---|---|---|---|---|
| Lower bound | Upper bound | Lower bound | Upper bound | Lower bound | Upper bound | |
#ARRAY1 |
1 | 10 | - | - | - | - |
#ARRAY2 |
1 | 10 | - | - | - | - |
#X-ARRAY3 |
1 | eXtensible | - | - | - | - |
#X-ARRAY4 |
1 | eXtensible | 1 | 5 | - | - |
#X-ARRAY5 |
eXtensible | 10 | - | - | - | - |
#X-ARRAY6 |
1 | 10 | 100 | eXtensible | eXtensible | 1000 |
Examples of array definitions:
#ARRAY2(I4/10) /* a one-dimensional array with 10 occurrences (1:10) #X-ARRAY4(I4/*,1:5) /* a two-dimensional array #X-ARRAY6(I4/1:10,100:*,*:1000) /* a three-dimensional array
In a parameter data area, you may specify an array with a variable
number of occurrences. This is done with the index notation 1:V.
Example 1: #ARR01 (A5/1:V)
Example 2: #ARR02 (I2/1:V,1:V)
A parameter array which contains a variable index notation
1:V can only be redefined in the length of
its elementary field length, if the 1:V index is
right-most; for example:
#ARR(A6/1:V) can be redefined up to a length of 6
bytes
#ARR(A6/1:2,1:V) can be redefined up to a length of
6 bytes
#ARR(A6/1:2,1:3,1:V) can be redefined up to a length
of 6 bytes
the product of the right-most fixed occurrences and the elementary field length; for example:
#ARR(A6/1:V,1:2) can be redefined up to a length of
2*6 = 12 bytes
#ARR(A6/1:V,1:3,1:2) can be redefined up to a length
of 3*2*6 = 36 bytes
#ARR(A6/1:2,1:V,1:3) can be redefined up to a length
of 3*6 = 18 bytes
A variable index notation 1:V cannot be used within a
redefinition.
Example:
DEFINE DATA PARAMETER 1 #ARR(A6/1:V) 1 REDEFINE #ARR 2 #R-ARR(A1/1:V) /* (1:V) is not allowed in a REDEFINE block END-DEFINE
As the number of occurrences is not known at compilation time, it must
not be referenced with the index notation (*) in the statements
INPUT,
WRITE,
READ WORK FILE,
WRITE WORK FILE. Index
notation (*) may be applied either to all dimensions or to none.
Valid examples:
#ARR01 (*) #ARR02 (*,*) #ARR01 (1) #ARR02 (5,#FIELDX) #ARR02 (1,1:3)
Invalid example:
#ARRAYY (1,*) /* not allowed
To avoid runtime errors, the maximum number of occurrences of such an
array should be passed to the subprogram/subroutine via another parameter.
Alternatively, you may use the system variable
*OCCURRENCE.
Notes:
1:V is
used as a local data area (that is, specified in a
DEFINE DATA LOCAL
statement), a variable named V must have been defined as
CONSTANT.
1:V cannot be used in
conjunction with BY
VALUE.