Programming 3 – 31
Here is another sample program that uses a FOR-NEXT loop to print all
the possible combinations of dots and spaces in numeric order:
10 REM SAMPLE 2
20 WIDTH “LPT1:”,255
30 NDOTS = 256 ‘MAXIMUM POSSIBLE COMBINATIONS
40 LPRINT CHR$(27);CHR$(75);CHR$(NDOTS MOD 256);
CHR$(FIX(NDOTS/256));
50 REM START GRAPHICS 256 COLUMNS
60 FOR I=0 TO NDOTS-1
70 LPRINT CHR$(I);
80 NEXT I
90 PRlNT:REM LINE FEED
A word of explanation about line 20. The IBM Personal Computer is set
for a maximum line length of 80 characters, so it adds a Carriage Return
and Line Feed after the 80th character. Because the data for each column
is treated as a character, your computer will send CR and LF codes after
the data for the 80th column, and the printer will interpret these codes
as graphics information and print them. A WIDTH statement changes
the maximum length of a line, and placing the number 255 in a WIDTH
statement eliminates any length restriction. (See your IBM BASIC Manual
for details.)
The printout looks like this:
