You can move the copy cursor elsewhere on the screen at any time whilst

copying, so you can copy sections from several different lines to create a

completely new line. If you want to abandon editing a line half-way through,

press . Do not press , as your old line will be replaced by the

partially-edited version.

AUTO

Earlier you saw that program lines are usually numbered in tens. This leaves

plenty of free line numbers for any statements that are inserted later. If you

wish, the computer can automatically number lines for you. Remove the

current program using NEW and then type:

AUT0

The computer prints 10 and waits for you to type a statement. Type the

following, remembering to press after each line. (You can still use the

editing facilities: most of line 40 can be copied from line 20, for example.)

10 PRINT "A short program"

20 PRINT "What is your first number " ;

30 INPUT first

40 PRINT "What is your second number " ;

50 INPUT second

60 PRINT first; " plus ";second; " gives "; first+tsecond

After the last line the computer prints 70. As the program is complete, press

-- you no longer want the computer to generate new line numbers. You

can now LIST or RUN the program.

AUTO can be used to begin numbering at any line number, with any interval

in between. The default interval is ten, so AUTO 100 produces line 100, 110,

120 and so on. AUTO 15,1 would produce line numbers 15, 16, 17 etc.

LIST

You have already used LIST, but an extended LIST command is also available

which is useful as a cross-reference in longer programs. Try typing:

LIST IF PRINT

and

LIST IF first

In other words LIST IF displays only those lines containing the specified

sequence of characters.

C 8