Commodore Plus 4 - Page 50

38 The BASIC Language
do, the ending point of the first line segment becomes the starting point of the
next line segment, etc.
Examples: 5 GRAPHIC 1,1
10 DRAW, 30,25 TO 289,150 Draws a line from column 30,
row 25 to column 289, row 150.
20 DRAW, 160,25 TO 310,50 TO Draws a four-sided open shape.
240,100 TO 160,100 TO 80,50
30 DRAW TO 319,50 Draws a line from the current
pixel-cursor location to column
319, row 50.
DS Abbr. none
You can PRINT DS to display a reading of the disk drive error number, or you
can examine DS in a program when you need to know the drive status. Use DS
with DS$ to find out why the red error light on the disk drive is blinking after a
disk operation such as DLOAD. If no error occurred, DS is zero.
DS$ Abbr. none
You can print DS$ to display a message explaining the drive status. Use DS$
with DS to find out why the red error light on the disk drive is blinking after a disk
operation such as DLOAD. The error messages are listed in Appendix A.
DSAVE Abbr. dS
DSAVE file name, Ddrive, Uunit
Stores the current program onto a disk. You cannot use DSAVE to store
programs onto cassette tape.
Parameters: "file name", D drive number, U unit number
1. You must include the name of the file. Enter the name in quotes. You can
use a variable name in place of the file name, but the variable must have a value,
and it must be in parentheses (not in quotes).
2. Drive numbers are either 0 or 1. No other numbers are allowed. The default
value is 0. You do not need this parameter if you are storing onto a single disk
drive.
3. Unit number is an optional parameter. Use it only if you have more than one
disk drive connected to your computer and you are using a device other than unit
8 in the loading procedure. You must precede the unit number with U. You can
also type ON before U and the unit number, but ON is not required.
Note: The drive and unit number parameters and the file name can be speci
fied with a variable or expression in parentheses.