It goes like this....

"Write a menu-driven program which will convert sterling to a choice
of any 4 foreign currencies with the appropriate exchange rate being passed
as a parameter into a single procedure which can perform all conversions
and pass back out the exchanged amount."

I don't want anybody to write this for me but I just want to know
why I would want to pass the exchange rates into the proc as parameters
instead of just having variables or constants which are global to both
sub-programs holding the ex rates? The exrates will have to be stored
somewhere so they might as well be used by the proc as they stand?

Thanks in advance, s'cuse any non-programmerisms, I'm only learning :)

What exact language are you doing this in? It's just the menu bit seems the
hardest section whilst the conversion-in-a-fucntion bit is a doddle.

Ok, thanks for the help everybody, its appreciated, better go and
get those parameters in order...

Tom; The course I'm following is kind of modular, introducing a few
new statements and concepts at a time, I've just got onto procedures
but the menu bit was completed a couple of weeks back -though I've
just written my own proc to draw a configurable border around a window!
(I am very proud! its all parameter-based too, everybody'll be glad to
hear!=) which has made it look nicer, I'm using TP7 as far as I know.

Thanks again..

procedure Convert; begin Gout := GInp * GRate; end;
GInp := 123.456; GRate := 1.123;Conv; writeln('result1=', Gout );
GInp := 344.555; GRate := 4.567;Conv; writeln('result2=', Gout );
GInp := 567.533; GRate := 9.221;Conv; writeln('result3=', Gout );

--------------

function Convert( Ginp, GRate: real ): real;
begin Convert := GInp * GRate; end;

writeln('Result1 = ', Convert( 123.456, 1.123 ) );
writeln('Result2 = ', Convert( 344.555, 4.567 ) );
writeln('Result3 = ', Convert( 567.533, 9.221 ) );

Also, in complex programs, with either recursion, or multi-tasking
going on,  you might have several calls to Convert going on at the
same time.  The global variables would then step all over each others
values.

In larger programs, you might have dozens of procedures, and keeping
track of what global variables are in use at any point can get too
confusing.  using parameters and local variables can help clear up
this confusion.

So in general, parameters are a GOOD THING. The program runs better
and looks better too.  Well worth the slight extra initial effort.