Re: If Then function

["Tom Sprunger" <tlsprunger@xxxxxxxx>]

Computer languages have two possible results when you use an IF statement.
When the IF is evaluated as True, the instructions associated with the IF
are executed (the Then).  When the IF is false,  the next line of code is
executed.  The program completes the logical IF, Then, Else test by going to
a predefined Else action.

The Else statement (in computer language) allows a conditional branch to
some action other than the predefined next line of code. Else tells the
computer what to do in the case that the IF evaluation is false and you
don't want to go to the next line of code (predefined Else action).

So in the statement with no Else, the "Else" action is assumed.  Its still
there logically, its just not required for the programmer to input it.

So, no,  computer languages do not  explicitly require an Else statement.
But, every computer language has a implicit Else statement built in that the
program uses to decide what the action will be for a false evaluation of the
IF statement if the programmer does not explicitly define it with the use of
an Else.  From a logical standpoint you must have an action for a false
evaluation, even if it is "continue what you were doing before the IF was
evaluated".

Same is true for humans.  You must have a predetermined action for a False
evaluation of IF.  Example.  You are driving down the street.  You come to a
stoplight. IF the light is red, Then you stop.  What do you do if it isn't
red?  You keep going.  That is because you have predefined that the action
for a false IF evaluation is to continue what you were doing before the
light turned red.  However, you could just as easily have predetermined that
you turn right If the evaluation of the stoplight color is not red.

The point is that logically any time you have a test you have a decision
which by definition has at two possible outcomes (boolean logic). That is
the point I was making. You have to define both outcomes either implictly or
explicitly.

Too picky?

Tom


----- Original Message -----
From: "Mike Campbell" <ug@xxxxxxxxxxxx>
To: <metastock@xxxxxxxxxxxxx>
Sent: Wednesday, December 27, 2000 3:15 PM
Subject: Re: If Then function


>
> >> An IF function must have an Else as well as a Then to be logically
> >> correct. It is impossible to have no Else without violating the
> >> rules of logic. It would make no sense to either a computer or a
> >> human.
>
> Can you name me a computer language that requires an else statement?
>
> Neither computers nor humans *require* an else.