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STRING

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STRING variables or literal values are one byte per character length text or ASCII characters.


Syntax:

DIM variable AS STRING [* byte_length]


  • Byte length is optional in DIM statements, but is required in TYPE definitions as a literal or constant INTEGER value.
  • Literal strings are defined by quotation marks on each end. The quotes will not PRINT to the screen.
  • Quotation marks cannot be placed inside of literal string values! Use CHR$(34) to display " quotes.
  • Semicolons and commas outside of the string can be used to combine strings in a PRINT statement only.
  • LEN determines the number of bytes or number of string characters that are in a particular string.
  • Literal string ends are designated by quotation marks such as: "text". Use CHR$(34) to add quotes to string values.
  • Variable suffix type definition is $ such as: text$.
  • NOTE: Many Qbasic keyword variable names CAN be used with a STRING suffix($) ONLY! You CANNOT use them without the suffix, use a numerical suffix or use DIM, REDIM, _DEFINE, BYVAL or TYPE variable AS statements!


Creating a fixed length STRING variable in Qbasic:
  • Variable$ = " " ' 1 space creates a one byte string length in a procedure(not fixed)
  • Variable$ = SPACE$(n%) ' defined as a n% length string in a procedure(not fixed)
  • DIM variable AS STRING * n% ' fixed string length cannot be changed later
  • Variable AS STRING * n% ' fixed string length in a SUB parameter or TYPE definition.
  • CONST variables can also be used after the constant value is defined.


QB64 fixed length string type suffixes
  • A number after the string variable name $ suffix denotes the fixed string length: X$2 denotes a 2 byte string.


String Concatenation (addition)
Must be used when defining a string variable's literal value!
  • Concatenation uses the + addition symbol to add literal or variable parts to a string variable value.
  • Quotation marks cannot be added. Use CHR$(34) as quotes are used to define the ends of strings.
  • Numerical values added must be converted to strings in string variable definitions. See the STR$ function.
  • Concatenation can be used in PRINT statements along with semicolons and commas used by PRINT ONLY.
  • Semicolons or commas outside of quotes cannot be used to make a string variable's literal string value!


Example 1: Using a string type suffix with a fixed length byte size in QB64 only. The number designates the fixed string length.

var$5 = "1234567" PRINT var$5

12345

Note: The suffix must keep the same byte length or it is considered a different string variable with a different value!


Example 2: Creating a string variable value by adding variable and literal string values. This procedure is called string concatenation.

age% = 10 a$ = "I am " + CHR$(34) + LTRIM$(STR$(age%)) + CHR$(34) + " years old." b$ = "How old are you?" question$ = a$ + SPACE$(1) + b$ PRINT question$

I am "10" years old. How old are you?

Note: Since quotation marks are used to denote the ends of literal strings, CHR$(34) must be used to place quotes inside them.


Example 3: How QB64 string type suffixes can fix the length by adding a number of bytes after it.

strings$5 = "Hello world" PRINT strings$5

Hello


See also:



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