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Chapter 6
Line 10 sets the top-to-top line spacing at 7 dots.
Lines 20 and 30 KICK the printer into graphics mode. N specifies the
number of graphic columns. By making it a variable, we can easily change
it later, right within a program, to print graphic lines of different lengths.
As a preliminary software test before things get too complicated, we'd better
check the line spacing. Add these lines:
FOR X=1 TO
25
FOR C = 1 TO 50 : PRINT CHR$ (127);
40
501 PRINT : NEXT X
and we should always return the line spacing to its "normal" power-up
. . .
figure of 12 by ending every program with:
900 PRINT CHR$ (27) "2"
999 PR #0
Now we can RUN.
After 3 passes of the print head, our printout should look like this:
What Are We Trying To Do?
We are creating a universal program that will READ and process large amounts
of DATA, and is simple to use. READ and DATA statements are used since the
DATA need be entered in the program only once, and DATA lines are easily
edited. Think about this paragraph and understand it since the going will get
rougher before it gets easier.
Let's delete lines 25 and 50 and change line 20 so it will READ in a value of N,
the number of dots to be printed in a specific row:
READ N : P R I N T T A B ( 1 0 ) ;
20
50
3
(Non-Apple owners use END instead)
Figure 6-1
: NEXT C
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