If you add another line to the program the computer automatically puts the

lines into line number order. For example, type:

3 PRINT "This is another Line"

and LIST the full program.

Program lines are usually numbered in tens as this makes it easy to insert

extra lines later. If you type:

RENUMBER

the computer automatically renumbers the program, making the first line 10.

Once a program is complete it can be saved onto disc so that it can be used

again. The Welcome software contains a series of programs which have been

saved in this way. You probably don't want to save the present program, so

type:

NEW

which tells the computer to 'forget' the program -- you can confirm this by

trying to LIST it.

You may accidentally lose a program by pressing , or by typing NEW

before you realise that you have not saved a copy of the program. Normally, the

program can be recovered provided no new program lines have been typed. Use

the command:

OLD

to restore the old program.

A simple program using variables

Throughout this section and the remainder of the chapter, you will be required

to type a number of short programs and, for clarity, we shall omit the

symbol at the end of each line.

Type the following program in:

10 PRINT "Can you give me a number ";

20 INPUT yournumber

30 PRINT "You typed ";yournumber

and then RUN the program. The computer obeys line 10 and displays the

question :

Can you give me a number ?

The question mark is added automatically by the execution of line 20. The

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