DATA
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The DATA statement creates a line of fixed program information separated by commas. The DATA can be later READ by the program at runtime.
Syntax
- DATA [value1, value2, ...]
Description
- DATA is used at the beginning of every data field line with commas separating the values that follow.
- Values can be any literal STRING or numerical type. Variables cannot be used.
- DATA fields can be placed and READ consecutively in the main program code body with or without line labels for RESTORE.
- DATA is best placed after the main program code.
- RESTORE will only read the first data field if the DATA is not labeled or no label is specified in a RESTORE call.
- When using multiple DATA fields, label each data field with a line label so that each data pointer can be reset for multiple reads with RESTORE linelabel.
- QBasic comma separations were flexible to allow column alignments when creating them. QB64 removes spacing between commas.
- STRING DATA values with end spaces, QBasic keywords and values that include the comma character must be enclosed in quotation marks.
- DATA fields can only be created by the programmer and cannot be changed by a user or lost.
- Comments after a data line require a colon before the comment.
- If a READ statement attempts to read past the last data value, an "Out of Data" error will occur. Use end of data markers when necessary.
- DATA fields can be placed after SUB or FUNCTION procedures, but line labels are not allowed.
Examples
Example 1: Creating two DATA fields that can be READ repeatedly using RESTORE with the appropriate line label.
RESTORE Database2 READ A$, B$, C$, D$ 'read 4 string values from second DATA field PRINT A$ + B$ + C$ + D$ 'note that quoted strings values are spaced RESTORE Database1 FOR i = 1 TO 18 READ number% 'read first DATA field 18 times only PRINT number%; NEXT END Database1: DATA 1, 0, 0, 1, 1, 0, 1, 1, 1 DATA 2, 0, 0, 2, 2, 0, 2, 2, 2 : ' DATA line comments require a colon Database2: DATA "Hello, ", "world! ", Goodbye, work! |
Hello world! Goodbyework! 1 0 0 1 1 0 1 1 1 2 0 0 2 2 0 2 2 2 |
Example 2: How to RESTORE and READ DATA in a SUB procedure in QB64. Line labels can be used for multiple DATA fields.
DIM SHARED num(10) 'shared array or must be passed as a parameter ReadData 2 '<<<<<<< change value to 1 to read other data FOR i = 1 TO 10 PRINT num(i); NEXT END SUB ReadData (mode) IF mode = 1 THEN RESTORE mydata1 ELSE RESTORE mydata2 FOR i = 1 TO 10 READ num(i) NEXT mydata1: DATA 1,2,3,4,5,6,7,8,9,10 mydata2: DATA 10,9,8,7,6,5,4,3,2,1 END SUB |
10 9 8 7 6 5 4 3 2 1 |
See also