Apple II User Manual

B$="BASIC FOR"+" "+A$

PRINT B$

BASIC FOR ROCKWELL R6500

Concatenation is especially useful if you wish to take a string apart and then put it back together

with slight modifications. For instance:

C$=LEFT$(B$,9)+"-"+MID$(B$,11,8)+"-"+RIGHT$(B$,5)

PRINT C$

BASIC FOR-ROCKWELL-R6500

VAL AND STRS FUNCTIONS

Sometimes it is desirable to convert a number to its string representation, and vice-versa. "VAL"

and "STR$" perform these functions.

Try the following:

STRING$="567.8"

PRINT VAL(STRING$)

567.8

STRING$=STR$(3.1415)

PRINT STRINGS$,LEFT$(STRING$,5)

3.1415 3.14

"STR$" can be used to perform formatted I/O on numbers. You can convert a number to a string

and then use LEFT$, RIGHT$, MID$ and concatenation to reformat the number as desired.

"STR$" can also be used to conveniently find out how many print columns a number will take.

For example:

PRINT LEN(STR$(3.157))

If you have an application in which a user is typing in a question such as "WHAT IS THE VOLUME

OF A CYLINDER OF RADIUS 5.36 FEET, OF HEIGHT 5.1 FEET?" you can use "VAL" to

extract the numeric values 5.36 and 5.1 from the question.

CHR$ FUNCTION

CHR$ is a string function which returns a one character string which contains the alphanumeric

equivalent of the argument, according so the conversion table in Appendix E. ASC takes the first

character of a string and converts it to its ASCII decimal value.

One of the most common uses of CHR$ is to send a special character to a terminal.

100 DIM A$(15)

110 FOR I=1 TO 15

120 READ A$(I)

130 NEXT I

120 F=0:I=1

130 IF A$(I)<=A$(I+1) THEN 180

140 T$=A$(I+1)

150 A$(I+1)=A$(I)

160 A$(I)=T$

170 F=1

180 I=I+1

185 IF I<15 THEN 130

190 IF F THEN 120

200 FOR I=1 TO 15

202 PRINT A$(I)

204 NEXT I

220 DATA AIM 65,DOG

230 DATA CAT,R6500

240 DATA ROCKWELL,RANDOM

250 DATA SATURDAY,"***ANSWER***"

260 DATA MICRO,FOO

270 DATA COMPUTER,MED

280 DATA NEWPORT BE-ACH,DALLAS,ANAHEIM