Apple II Additional String Considerations, Name Example PURPOSE/USE DIM, Input Input X$, Del

ADDITIONAL STRING CONSIDERATIONS

1.A string may contain from 0 to 255 characters. All string variable names end in a dollar sign ($); for example, A$, B9$, K$, HELLO$.

2.String matrices may be dimensioned exactly like numeric matrices. For instance,

DIM A$(10,10) creates a string matrix of 121 elements, eleven rows by elevon columns (rows 0 to 10 and columns 0 to 10). Each string matrix element is a complete string, which can be up to 255 characters in length.

NAME	EXAMPLE	PURPOSE/USE
----	-------	-----------
DIM	25 DIM A$(10,10)	Allocates space for a pointer and length for
		each element of a string matrix. No string
		space is allocated.
LET	27 LET A$="FOO"+V$	Assigns the value of a string expression to
		a string variable. LET is optional.
=		String comparison operators. Comparison
>		is made on the basis of ASCII codes, a
<		character at a time until a difference is
<= or =<		found. If during the comparison of two
>= or =>		strings, the end of one is reached, the
<>		shorter string is considered smaller.
		Note that "A " is greater than "A" since
		trailing spaces are significant.
+	30 LET Z$=R$+Q$	String concatenation. The resulting string
		must be less than 256 characters in length
		or an LS error will occur.
INPUT	40 INPUT X$	Reads a string from the keyboard. String
		does not have to be quoted; but if not,
		leading blanks will be ignored and the
		string will be terminated on a "," or ":"
		character.
READ	50 READ X$	Reads a string from DATA statements
		within the program. Strings do not have
		to be quoted; but if they are not, they
		are terminated on a "," or ":" character
		and leading spaces are ignored. See
		DATA for the format of string data.
PRINT	60 PRINT X$	Prints the string expression on the
	70 PRINT "FOO"+A$	display/printer.

300STATEMENT DEFINITIONS

301SPECIAL CHARACTERS

CHARACTER USE

--------- ---

@Erases current line being typed, and types a carriage return/line feed.

DEL	Erases last character typed. If no more characters are left on
	the line, types a carriage return/line feed.
RETURN	A RETURN must end every line typed in. Returns cursor to
	the first position (leftmost) on line, and prints the line if the
	printer is on.
F1	Interrupts execution of a program or a list command. F1 has
	effect when a statement finishes execution, or in the case of
	interrupting a LIST command, when a complete line has
	finished printing. In both cases a return is made to BASIC's