Commodore 128D - Dimensioning Arrays

lates the total, just as it did before, but you must
use a subscripted variable to do it.
After you run the program, if you want to recall
the third number, type ?X(3)<RETURN). The
computer remembers every number in the array
X. You can create string arrays to store the char
acters in string variables the same way. Try
updating the COMMODORE 128 COMPUTER
READ-DATA program so the computer will
remember the elements in the A$ array.
5 DIM A$(3)
10FORJ-1 TO 3
20 READ A$(J)
30 ? A$(J)
40 NEXT
50 END
60 DATA COMMODORE,C128,COMPUTER
TIP: You do not need the DIM statement in your
program unless the array you use has more than
10 elements. See DIMENSIONING ARRAYS.
Dimensioning Arrays can be used with nested loops, so the
Arrays computer can handle data in a more advanced
way. What if you had a large chart with 10 rows
and 5 numbers in each row. Suppose you
wanted to find the average of the five numbers
in each row. You could create 10 arrays and
have the computer calculate the average of the
five numbers in each one. This is not necessary,
because you can put all the numbers in a two-
dimensional array. This array would have the
same dimensions as the chart of numbers you
want to work with—10 rows by 5 columns. The
DIM statement for this array (we will call it array
X) should be:
10 DIM X(10,5)
This tells the computer to reserve space in its
memory for a two-dimensional array named X.
The computer reserves enough space for 50
numbers. You do not have to fill an array with as
many numbers as you DIMensioned it for, but
the computer will still reserve enough space for
all of the positions in the array.
62 USING C128 MODE—Advanced BASIC Programming