Commodore Plus 4 - Page 143

—- tain any of the following characters: SPACE, colon, or comma. If two
commas have nothing between them, the value will be READ as a zero
for a number, or an empty string. Also see the RESTORE statement.
which allows the Plus/4 to re-read data.
— EXAMPLE:
DATA 100, 200, FRED, "HELLO,MOM'1, , 3, 14, ABC123
DEF FN DEF FN name (Var/'ab/eJ = expression
(DEFine FunctioN)
This command allows you to define a complex calculation as a func-
tion. In the case of a long formula that is used several times within a
program, this can save a lot of space. The name you give the function
begins with the letters FN, followed by any legal numeric variable
name. First you must define the function by using the statement DEF
followed by the name you have given the function. Following the name
— is a set of parentheses {) with a numeric variable (in this case, X) en
closed. Then you have an equal sign, followed by the formula you want
to define. You can "call" the formula, substituting any number for X,
using the format shown in line 20 of the example below:
EXAMPLE
10 DEF FNA(X) = 12*(34.75-X/.3) + X
20 PRINT FNA(7)
The number 7 is in
serted each place X
is located in the for
mula given in the
DEF statement.
— DIM DIM vanable (subscripts) \,vanable(subschp(s)]...
Before you can use an array of variables, the program must first exe
cute a DIM statement to establish the DIMensions of that array (unless
there are 11 or fewer elements in the array). The statement DIM is fol
lowed by the name of the array, which may be any legal variable name.
Then, enclosed in parentheses, you put the number (or numeric vari-
— able) of elements in each dimension. An array with more than one di
mension is called a matrix. You may use any number of dimensions,
but keep in mind that the whole list of variables you are creating takes
up space in memory, and it is easy to run out of memory if you get car-
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