LI-COR LI-6400, Manual

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LPL Topics
Array Operations
Using the LI-6400 23-11
pets of LPL code that illustrate differences between declaring arrays and dy-
namic allocation of arrays.
The INT array scores exists for the entire time the program is active. The local
array text exists only while the function TestFct is active. A 1000 element
FLOAT array that is created in TestFct by the sequence
FLOAT 100 MAKE IF RETURN THEN
:PTR values
The keyword MAKE expects two values on the stack: the size of the array to
be created, and a number indicating the type of array to create. We indicate
type by the keyword
FLOAT (note that itÕs FLOAT , not :FLOAT !). If
MAKE
succeeds (if thereÕs enough space to make the array), then the address
of the new array is pushed onto the stack, followed by a 0. If MAKE fails,
only a 1 is pushed onto the stack. When
MAKE
succeeds, it is up to you to
keep track of the address for future reference, and this is usually done by as-
signing a
PTR
to it. In Figure 23-5, a local
PTR
is assigned; we can do that
because the array is deallocated (using FREE ) before the function is done. If
we wanted to use the new array after the creating function terminates, we
would want to be sure to assign a global
PTR to the arrayÕs address.
Figure 23-6 illustrates how to do this.
/* scores is a global array */
:INT
scores[20] {1 2 3 4 5 6 7 8 9 10}
:FCT
Main { ... testFct ...}
TestFct
{
/* text is a local array */
0
:CHAR
text[80]
"This is a test" text =
...
/* Allocate a 1000 element float array.*/
FLOAT
1000
MAKE IF RETURN THEN
:PTR values
...
/* Dispose of the float array */
values
FREE
}
Figure 23-5. Program outline illustrating use of
MAKE
and
FREE
.