Atari 400

50 User's Handbook to the Atari 400 /8 00 Computers
An array can also consist of two dimensions . Such an array is
known as a two-dimensional array (or table). An example of an
array
of 4 rows and 3 columns is shown in Illustration 3-2.
A
two-dimensional array contains two subscripts. The first
subscript
contains the row location , while the second subscript
contains
the column location . The subscripted variable A(l , O)
identifies the darkened area in the array shown in Illustration 3-
2.
Illustration 3-2. Two-Dimensional Array
Columns
°
1
2
°
1
Rows
2
3
I n the Atari BASIC, arrays can be used to represent numeric data.
String arrays
cannot be used in Atari BASIC.
Before any array variable can be us ed in a program , the size of
that array must have been defined so that BASIC can reserve a
memory area for it. This is also accomplished with the DIM
statement. A single dimension num eric array with 11 variables
could be defined with the following DIM statement:
DIM A(10)
Remember that array subscripts begin with 0. The refore , the
numeric array A which was dimensioned in the preceding
statement, would have space reserved for the 11 array elements,
not 10 .