nc ramming tips Error messages
| ma, p Two pageS there are some Writing programs 'There are usually several different a a dat jski pa
MAbcip you write yourowTI | ways to write a program and some of program and the messages are explained
MA ms. anda list of the most eri ihe computer them may be neater and shorter than in the computer's manual. Here are some
s ton budgs y0U might gel, and can Carry Cut three mainactivities: others. When you are writing a long of the most cormnmon messages you may
s, bv hkel : z e | program it is a good idea to divide it up get
iEfuses them The most likely simple instructions, repeating things JE of sections with subrcutines
SEJ havea | and making decisions. These are the | into lotsof to Hi
Sčere listed first. sO if you ha Ons. carry out each activity. The central core 4 This means there are not
gla which will not work. building blocks of all programs. ; ofthe program may bea simple seto! Outof enough data items for the
čičihrough this list until you find instructions, decisions and repeats data computer to read in the
a« which controls when and how often the DATA lines. lt may be
computer carrjes out the subroutines. because you have missed
out a comma between two
items, so the computer has
read them as one
Calculating
p The line with the number
given in a GOTO or GOSUB
4 statement does not exist. žolna
REPEATING Wi FORJ-! TO 6 You may have accidentally
THINGS 3 Getting mo: erased the line by typing in
20 LET A-l | information another line with the same
number, or you may have

30 IFA< 10 THEN
just mistyped the number

Mlortyping mistakes in BASIC words.

u misspel one of these words the

puter will not recognize il. No such 4 You may get this report

oj variable on a BBC or Sinclair

computer. lt usually means
you have not set upa
variable with a line such as
LETC<0ao LETC:-""

before using it.

Na xa
ck Os and Os and Is and Is to make
have typed the right ones inthe

s
ac

Last word
Some bugs ale VETy
(the computer v

Make sure you use the correct RND, PLOT
and CLS commands for the computer.
Check, too, that you have giventhe

TOME - ej

Make sure you have not lef out
er, makesure zrači

guotation marks, or the commas between

NE —
Mave a Sinclair comput

da peda word in letter by data items. Check complicated lines
es pressing the key for that which have lots of symbols especially computer a general graphics line ifit
carefully. needs one.