3. Type in the program "CHARACTERS" again, & then type
 
 
LET
 X=7
 
so that - although it doesn't appear in the program - the computer now contains a variable X with value 7. 
Now save the program, turn the computer off & on (to make sure there's no cheating), & load the program 
back again. Type
 
 
PRINT
 X
 
& you will get the answer 7. The 
SAVE
 statement saved not only the program, but also all the variables - 
including X.
 
    If you want to keep these variables when you execute the program, you must remember to use 
GOTO
& 
not 
RUN
 (as was mentioned in chapter 9). You can avoid having to remeber this by making the program 
execute itself (using 
SAVE
 as a program line).
 
4. Type in a very long program, & them momentarily disconnect the power supply. This sort of thing 
sometimes happens spontaneously; it is not a bug, but a glitch. There is nothing you can do about it except 
cry. It if happens more often than you can bear then there is probably something wrong, but it would be 
worth saving the incomplete program on tape half-way through.