SECTION B - PRIMER FILE : PRIMER.B
MATHEMATICS
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Mallard Basic supports a good range of mathematical functions, which
means that it can be used for technical and accountancy programs
when required. This section deals with simple arithmetic only;
addition,subtraction, division and multiplication. This is essential
knowledge, and if this is all you need don't bother to go any
further. More information can be found in the advanced section if
you need it, but knowledge of maths is required
We look first at the operators (signs) for the four basic func-
tions; addition + ,subtraction - , division /,and multiplication *.
The first two will be familiar (+ and -) but the other two may be a
little strange. The * may be completely new, but the / is the same
as in a fraction 3/4, which is, after all, a division sum. This is
only a passing comment ,as BASIC does not work in fractions, only
decimals ( although fractions such as 6, (, 7 ,) can be printed)
We saw,in section A that numbers can be printed alone or inside
double quote marks. The difference shows in this section. If you
print " 6+4" you get 6+4 on the screen , but leave out the quote
marks and the computer works out the sum for you .You will see in
the listing that follows how to make good use of this to write
complete sums such as 6+4= 10.
MALLARD BASIC does it's arithmetic in the same way as us, which
is not true of all languages. In other words you don't need to learn
new tricks. It also uses standard protocol; that is if you are doing
a sum with mixed operators, it will do multiplication and division
first, then addition and subtraction. If you want things done in a
different order, you use brackets , as you would normally do. For
example (6+4)*3= 30 ; but 6+4*3=18.
A snag with MALLARD BASIC (which it shares with most
calculators) is that large and small numbers are printed as scaled
numbers (scientific format)
Thus 0.042 decimal might be shown 4.2E-2 which means 4.2 x(10
to the power of -2).
This probably won't bother you as the range of unscaled (ordinary
decimal) numbers is quite wide.
Floating point is supported too; that is you can put in decimal
numbers with varying decimal places and the computor will accept and
process them :for example 34.2 : 234.347 : 0.04, etc., but note
that leading and trailing zeros are discarded ;that is 45.340 will
print as 45.34 and 007 will print as 7. If you need to print this
type of number it must be surrounded by quote marks. e.g "007" but
then it can't be processed mathematically, because the computer will
recognise it only as a string.
Numbers can be entered and printed in columns with the decimal
points in line as is often needed when making tables for statistical
work or dealing with sums of money. This is known as formatted
printing and is touched on briefly in this section.
The listings which follow are designed to illustrate the points
mentioned above. Please experiment as much as you like, as described
in the file INTRO.D. Don't take anything for granted but try it for
yourself.
End of file PRIMER.B
ing for granted but try it for
yourself.