EasyManua.ls Logo

Radio Shack TRS-80 Model III - Page 175

Radio Shack TRS-80 Model III
274 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Loading...
BASIC
CHR$ may also be used
to display any
of the
graphics or special
characters. (See
Appendix
C,
Character Codes
.
)
460
CLS
470
FOR I
=
129
TO 191
480
PRINT I;
CHR*U>>
490
NEXT
500
GOTO 500
(RUN the program
to see the
various graphics
characters.)
Codes
0-3
1 are
display control codes
. Instead of
returning an actual display
character,
they return
a
control
character. When the
control character is
PRINTed,
the function
is performed. For example,
23 is the code
for 32
character-per-line
format; so the
command, PRINT CHR$(23)
converts the
display format to 32
characters
per line. (Hit CLEAR, execute
CLS, or execute
PRINT CHR$(28)
to return to
64
character-per-line format.)
FRE (string)
When used with a
string variable or string
constant as an
argument, returns the
amount of string storage space
currently
available
.
Argument
must
be
enclosed in
parentheses. FRE causes BASIC
to start searching
through memory
for unused
string
space . If your
program has done a
lot
of
string
processing
,
it may take
several
minutes to recover
all the "scratchpad" type
memory.
500
PRINT FRE(A$),
FRE(L$), FRE ("Z")
All
return the
same value.
The string used has no significance; it is a dummy
variable
.
See
Chapter
1
8
,
CLEAR n.
FRE(number) returns the
amount of
available memory (same
as MEM).
165

Other manuals for Radio Shack TRS-80 Model III

Related product manuals