The Teddy program runs in mode 130, which allows eight different colours, In
other modes, such as mode 129, only four colours can be displayed at the same
time. The range of colours is increased by four extra patterns made up of
various colour combinations. For example, in mode 129:
GCOL 16,0 red-orange
GCOL 32,0 orange
GCOL 48,0 yellow-orange
GCOL 64,0 cream
These colours are produced regardless of the second number used. The effect of
the commands varies from mode to mode, as the patterns are built up from the
colours available in that mode. Change the GCOL commands in the Teddy
program to see some of the patterns available in mode 130.
You can create your own colour patterns in place of those provided -- this is
described on page Bl3.
Printing text
Text can be displayed in any of the eight modes, but the number of characters
per line varies from mode to mode, and can be 20, 40 or 80 characters. Try:
10MODE 128
20 PRINT "Here is a sentence"
30 PRINT "to demonstrate printing."
Edit the program and run it a few times with line 10 altered to produce mode
129, 130 or 135. Mode 135 gives the clearest display. If you are using a TV
rather than a monitor you may find mode 128 text rather hard to read.
After obeying any PRINT statement the computer moves to the start of a new
line unless instructed to do otherwise. Run the program again after changing
line 20 to:
20 PRINT "Here is a sentence";
The semicolon at the end of the line tells the computer to stay on the same line
after printing the string. The result is:
Here is a sentence to demonstrate printing
The semicolon is useful if you are printing a variable within a sentence, and
want all the text to be on the same line. Add these lines:
40 my_age=105
50 PRINT "I am ";my_age;" years old."
The spaces within line 50 are very important, as they stop the text running
together untidily, as in the first example.
C 20