Chapter
3:
Programming the
VIC
20
Computer 89
The two-dimension grocery list variable, GL$, would be dimensioned
as follows:
DIM
OLS(3
..
5)
A
DIM
statement can provide dimensions for any number of variables,
providing the statement fits within an 88-character line.
The number
or
numbers following a variable name in a
DIM
statement
is
equal to the largest index value that can occur in that particular index
position. But remember, indexes begin
at
O.
Therefore, MP$(5) dimensions
the variable MP$ to have six values, not five, since indexes 0,
1,2,3,4,
and 5
will be allowed. GL$ (3,5), likewise, specifies a two-dimension variable with
24
entries, since the first dimension can have values
0,1,2,
and 3, while the
second dimension can have values 0 through
5.
Once you have declared
an
array variable in a
DIM
statement, you
must subsequently reference the variable with the specified number of
subscripts; each subscript must have a value between 0 and the number
specified in the
DIM
statement.
If
any of these syntax rules are broken, you
will get a syntax error.
Branch
Statements
Statements within a BASIC program normally execute in ascending
line number order. This execution sequence was explained earlier in this
chapter when
we
described line numbers. Branch statements change this
execution sequence.
GOTO
STATEMENT
GOTO
is
the simplest branch statement.
It
allows you to specify the
statement that will be executed next. Consider the following example:
213
FI"4.37
30
OOTO
'.1313
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