7-6
Section
Details of BASIC Commands
226
tron
Syntax:
TRON
[
M
]
Description:
Command. Turns ON the line number trace. If the
M
option is specified the line numbers will be
output to a trace buffer.
Remarks:
The
TRON
command activates a debugging tool that displays program line numbers in the order
they are executed by the BASIC interpreter and in the time required to change line numbers. If the
M
option is specified output will be redirected to a 255 element circular trace buffer.
The trace buffer has a battery backup, so its contents are retained even if the power is turned OFF.
When necessary, the
TRACE
command can be used to output the contents of the trace buffer to the
terminal.
The line number trace facility can be turned OFF using the
TROFF
statement.
If the ASCII Unit is reset or if the
NEW
statement is executed then the line number trace will
automatically be turned OFF.
Examples:
> 10 TRON
> 20 FOR A = 1 TO 5
> 30 NEXT A
> 40 TROFF
> 50 FOR A = 1 TO 5
> 60 NEXT A
RUN
[20][30][20][30][20][30][20][30][20][30][20][40]
>
See also:
TRACE
,
TROFF
val
Syntax:
VAL
(<string expression>)
Description:
Function. Converts a character string to a numerical expression.
Remarks:
<string expression> may be any character representation of a numeric value. If the character
representation does not represent a numeric value 0 will be returned.
All valid numeric expressions are acceptable, including hexadecimal, octal, single and double
precision floating point and exponential formatted numbers. Exponential formatted numbers must
be specified with an upper-case E or D.
Spaces in the numerical expression are ignored. The conversion will be terminated at the first
non-numerical character.
A value of 0 will be returned if the character string does not begin with a numeric character (+, -,
&, ., or a number). All numeric characters following a non-numeric character will be ignored.
Leading white space is stripped from the character representation before conversion.
Examples:
> 10 A$ = "2"
> 20 B$ = "3"
> 30 PRINT A$+B$
> 40 PRINT VAL(A$)+VAL(B$)
> RUN
23
5
>
See also:
STR
$
Summary of Contents for C200H-ASC11
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