Radio Shack TRS-80 PC-4 Owner's Manual page 38

a. Partial change
Example:
Change the
"+"
on line
20
of the previous example to"
*".
Operation:
• If the P0 program area is not designated, designate P0.
I:
510
~
ri
LP. __
~t
2._3_4_5_6_7_8_9 _
t._
Blinking means that a program is
written and this is the currently
designated program area.
• Call out line 20 using a LIST command.
LIST 20 III
• Move the cursor below the "+".
[ 510
20 _V=A+B-
I
510
20 V=A+B
*
If cursor movement keys
(~and
@]) remain pressed for more than 1 second, the
cursor will move quickly and continuously.
• Make the change.
0111
I
510
30
W=A-B_
*
Be sure to press the
lID
Key. If it is not pressed, only the display will change but
the program will remain unchanged.
• Press rD to release the change condition.
510
* Since any other key operation will result in an unnecessary change being made, avoid
pressing any other keys besides the
lID
and
rml
Keys.
Let's list the program and check the change.
~(@
LIST
II
READY PO
10 INPUT A,S
t - - - . - - - - ~ - - -
20 V=A*B
- - - - - - - - - _ . _ - - - - - -
30 W=A-B
40 PRINT V,W
50 END
READY P0
-35-