Atari 800 Basic Reference Manual

ASC
CHR$
7
STRINGS
This section describes strings and the functions as sociated with string handling.
Each string must be dimensioned (see DIM statement, Section 8) and each string
variable must end with a $. A string itself is a group of characters " strung"
together. The individual characters may be letters , numbers, or symbols
(including the Atari special keyboard symbols.) A substring is a part of a longer
string and any substring is accessible in Atari BASIC if the string has been pro-
perly dimensioned (see end of section). The characters in a string are indexed
from 1 to the current string length, which is less than or equal to the dimen-
sioned length of the string.
The string functions described in this section are:
ASC STR$
CHR$ VAL
LEN
Format: ASC(sexp)
Examples: 100A = ASC(A$)
This function returns the AT ASCII code number for the first character of the
string expression (sexp). This function can be used in either Direct or Deferred
mode . figure 7-1 is a short program illustrating the ASC function.
10 DH1 A$0:: 3)
20 A:f.=
11
P
30 A=ASC( A$)
40 PF.:H-H A
Figure 7-1. ASC Function Program
When executed, this program prints a 69 which is the AT ASCII code for the let-
ter "E". Note that when the string itself is u s ed, it must be enclosed in quotation
marks.
Format: CHR$ (a exp)
Examples: 100 PRINT CHR$ (65)
100 A$ = CHR$ (65)
This character string function returns the character, in string format,
represented by the A TASCII code number(s) in parenthes e s. Only one c ha r acter
is returned. In the above examples, the letter A is returned. Using the ASC and
CHR$ functions, the following program prints the upper ca se and lower case let-
ters of the alphabet.
Str-ings 37

Atari 800 Specifications

General

Brand	Atari
Model	800
Category	Desktop
Language	English