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' This example uses a recursive FUNCTION procedure (a function that calls
' itself) to find and return the length of a string.
 
' To try this example:
' 1. Choose New Project from the File menu
' 2. Copy the code example below to the code window
' 3. Press F5 to run the example
 
 DECLARE FUNCTION StrgLng% (X$)
 
 CLS                               ' Clear the screen
 INPUT "Enter a string: "; InString$
 PRINT "The string length is"; StrgLng%(InString$)
 
 FUNCTION StrgLng% (X$)
     IF X$ = "" THEN
          StrLng% = 0   ' The length of a null string is zero
     ELSE               ' Non-null string; make a recursive call
          StrgLng% = 1 + StrgLng%(MID$(X$, 2))
                        ' The length of a non-null string is 1 plus
                        ' the length of the rest of the string
     END IF
 END FUNCTION