LI-COR LI-6400, Manual

Page: 632 / 846

LPL Topics
Array Operations
23-10 Using the LI-6400
23
is passed to it.
PrintArray1
does it the hard way, but illustrates the use of
VAL
.
There is a variant of VAL called PVAL that is sometimes used with PTR ar-
rays. See Using PTR arrays on page 23-13.
Searching and Comparing Arrays
FIND is used to locate the occurrence of an element or group of elements (an-
other array) in an array. COS is used to tell if two arrays are identical in type,
ready value, and content (elements 1 through Ready only). Another tool -
SEARCH - is available if the array is a CHAR array that has an Path opened
to it (see Paths on page 23-41).
There is a variant of FIND called PFIND that can be used with PTR arrays,
described in Using PTR arrays on page 23-13. FIND and PFIND are illus-
trated in Figure 23-8 on page 23-15.
Dynamic Allocation
A declared array hangs around for the life of a function (if itÕs a local array)
or the life of the application. Sometimes it is efficient to dynamically allocate
an array. That is, create it when you need it, then dispose of it when youÕre
done, and recover that memory. Such arrays are created by the application
(
MAKE ), used, then disposed of ( FREE ). Figure 23-5 contains some snip-
:FCT
PrintArray1
{
/* Address of array assigned to ÕaÕ. */
:PTR
a
1 :INT i
/* Loop ÕREADYÕ times */
a
READY NLOOP
/* Get the ith value. */
a i
PICK VAL
"%d "
PRINT
/* Increment the counter */
&i 1 +
DROP
ENDLOOP
PrintArray2
{
:PTR
a
/* Much more efficient! */
a "%(* )d"
PRINT
}
Figure 23-4. Two methods to print the contents of a numeric array. Function
PrintArray1 illustrates the use of VAL , while PrintArray2 is much more efficient.