Origin - AMSTRAD cpc 6128 User Instruction

Note the use of the keyword NEW before typing in this program. This tells the
computer to clear any program in the memory (in a similar manner to [CONTROL]
[SHIFT] [ESC]). However the screen itself is not cleared.
The radius of the circle can be reduced by lowering the 190 figure (190 refers to
pixels).
To see the effect of the circle being plotted differently (in radians), delete line
20
from
the program by typing in:
20
To see a solid circle drawn by lines from the centre, edit line 50, replacing the word
pLo t with the word d raw. (Line 50 will then be):
50 draw 320+190*cos(a),200+190*sin(a)
Try this with and without line
20
again.
You will note that line 60 of this program is NE X T instead of NE X Ta. It is
permissible to simply type 'N E X T' on its own; the computer will work out which FOR
expression the
NE
X
T
is to be associated with. In programs where there are numerous
FOR and N
~
X T loops however, you may wish to add the variable's name after the
word
NE
X
T
in order to identify the
NE
X
T
statement when studying the program.
ORIGIN
In the preyious program we used the M 0 V E command to establish the centre of a
circle, then added the x,y co-ordinates to this centre position. Instead of adding these
centre co-ordinates to the point plotted, we can use the 0 RIG I N command. This will
position each of the x,y co-ordinates relative to the 0 RIG IN. To see this, type in:
new
10 cls
20 for a=1 to 360
30 origin 320,200
40 plot 190*cos(a),190*sin(a)
50 next
run
Foundation Course
Chapter 1 Page 61