Laser 128 - Def Fn

3.8 DEF FN
Purpose:
Format:
BASIC COMMANDS AND STATEMENTS
To define and name a function
that is written by the user.
DEF FN name (real variable)
expression.
Comments: The name is exactly the same as
a variable name. A user-defined
string function is not allowed:
Example:
The real variable is the variable
that will be used when the
function is evaluated.
The expression can be as long as
a line (239 characters long).
If you need to program
functions that require more
room than that, you should
implement your function as a
subroutine .
10 GEE= 9.8
20 DEF FN DIS(T)= GEE * T
;.. 2/2
30 INPUT "Time?";T
40 PRINT "Distance is";FN
DIS(T)
This would calculate the
distance that a body has fallen
after T seconds, using the
function DIS which is derived
from the formula s=l / 2gt
2
,
where s is the distance, g the
acceleration due to gravity, and
t the time that has elapsed since
the object was dropped from a
stationary position.
11-27