Experiment
#4
Writing Your Own Programs
By
now you should be able to write simple BASIC programs using the two
instructions PRINT and GOTO.
Before you go on experimenting with the spacing
in PRINT statements using the
comma and the semicolon, you should be aware
of
another useful command, the
NEW command.
When you enter the NEW command, any program that has been previously typed and
is
currently residing in working memory will be erased automatically.
Before you begin typing in a new program, you should always use the NEW
command to clear out the old program. Otherwise, you may end
-up
with a
combination
of
your new and old programs.
Assume that your old program still resides in memory:
10 PRINT
"HOW";
"NOW";
is
PRINT "SPLENDID
";
20 PRINT
"BROWN
";
"COW"
Now, without deleting this program, enter the following new program:
10 PRINT
"MY
COMPUTER
IS
A
";
20 PRINT "TOOL."
If
you list the program, you will find it
is:
LIST
10
PRINT
"MY
COMPUTER
IS
A
";
15
PRINT
"SPLENDID
";
20
PRINT
"TOOL."
K
Note that line
15
still exists because that line number was not used
in
the new
program.
So
remember, before typing a new program, clear the memory with the
command NEW. This won't be necessary, however,
if
you are certain that no program
exists
in
memory.
What you have learned:
In this lesson you have learned some commands
to
write and execute a simple BASIC
program. The PRINT and GOTO statements have been used to display simple
messages. Editing a BASIC program can be
accompli~hed
by retyping existing
line~
or
typing new lines. The NEW command is used
to
delete
an
entire program from
memory.
13
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