Bronze Edition Guide - True BASIC

12. Using and Storing Data 79
times it’s more convenient to put them right after a READ statement. You may use a separate
DATA statement for each item, or use commas to put several items on one statement.
True BASIC lumps all the DATA statements in a program together, in order, into one long
list of data items. Each time it executes a READ statement, True BASIC reads the next
item in the DATA list, regardless of where it appeared in the program.
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x READ and DATA statements can use either numbers or strings.
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You may freely mix strings and numbers in your DATA statements. Just be sure that the
variable name type (numeric or string) is reading an appropriate type of data item. You
can’t read a string data item into a numeric variable, but you can read a number into a string
variable. The TRIVIA program reads some numbers for the string variable answer$. This
is perfectly legal in True BASIC, as long as you don’t try to use that variable to do arithmetic
calculations.
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x You must put double quote marks around string data items that contain
commas, or around items that begin or end with spaces.
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If you don’t use quote marks, True BASIC will assume that any commas are separating data
items, and it will ignore any extra spaces before or after the data.
Checking for More Data
The TRIVIA program stores the number of questions in the first item in the DATA statements.
The number of questions then controls the FOR-NEXT loop so that it reads the correct
number of items. If the program tried to read more items than are contained in the
DATA statements, True BASIC would give you an error message.
It is not always convenient to count the number of DATA statement items, however. True
BASIC provides a way that you can use a DO loop to check whether there are any more data
items available. The SMOKY demo program you edited in the last chapter illustrates this
method. You haven’t learned the PLAY statement yet for performing music, but you should
be able to follow the logic of the program.
! Plays the beginning of
! “On Top of Old Smoky”.
DO while more data