Radio Shack TRS-80 Owner's Manual page 125

Examples
DEF
FNR(AtB) =
A
+
INT((B
- (A
-
1))
*
RNDC0))
This statement defines
function
fnr which
returns
a
random number between
integers
A
and B.
The
values for
A
and
B
are
passed
when
the
function
is
"called,"
i.e.,
used
in
a statement
like:
Y =
FNRtRl
>
R2)
If
ri
and R2
have been
assigned
the
values 2
and
8, this line
would
assign a
random number between
2
and
8 to y.
DEF FNL$<>!)
=
STRING*
(X.
"-")
Defines function
fnl$
which
returns a string
of
hyphens,
x characters long.
The
value for
x
is
passed
when
the function
is
called:
PRINT FNL*(3)
This
line
prints a string
of
30 hyphens.
Here's
an
example showing
deffn
used for a
complex computation-^
in
double-precision.
DEF
FNX*(A#» B*>
=
(A#
-
B*)
*
(A*
-
B#>
Defines function
fnx# which
returns the
double-precision value of the square of
the difference
between
a#
and
B#. The
values for
A#
and
B#
are
passed
when
the
function
is
called:
S# =
FNX*(A»» B«)
We
assume
that
values for
a#
and
b#
were
assigned elsewhere
in
the
program.
Sample
Program
710 DEF FNV(T)
=
(1087
+
S0R(273
+
T))/1G,52
720 INPUT "AIR
TEMPERATURE
IN
DEGREES CELSIUS"
I
T
730 PRINT "THE SPEED OF SOUND
IN
AIR OF"
T
"DEGREES
CELSIUS IS"
FNV(T)
"FEET PER SECOND,"
107