mas is series so I just typed[0].

But your function, as you defined it, expects a series and not a var.

I modified the code like this.

vars ma = series(GSMOOTH(Close[0],ma[0],Slowalfa));
vars maf=series(GSMOOTH(Close[0],maf[0],Fastalfa));

But it says this.
'ma' undeclared identifier

Why this occur? I defined a type of vars before ma.

Look at that line: you define ma using the return of a function that already needs ma. This can obviously not work. You must fill a series with some content before you can use it.

Aside from that, may I ask how your code is supposed to work? Even if you fix all the typing mistakes - there are a lot more - the script still makes not much sense to me. How and when do you want to enter a trade?

To fill series before using it, is this code right?

vars ma = series(0)

I trade just buy when the line is bule or the reverse.

The code is right, but then the series is just filled with 0, which is probably not what you need.

So I think I wrote the right code in the first post but you said it is wrong?

vars mas = series();
vars maf = series();

By writing this, everytime the bar is updated, mas and maf stored the latest value?

I want the latest value stores the last series.

Update:

This looks fine.

vars ma = series();
ma = series(GSMOOTH(Close[0],ma[0],Slowalfa[0]));
vars maf = series();
maf=series(GSMOOTH(Close[0],maf[0],Fastalfa[0]));

But again same one.
Where missing pointer?

'GSMOOTH' : Pointer expected
< ma = series(GSMOOTH(Close[0],ma[0],Slowalfa[0]));

The mas/maf definition is correct syntax-wise, it just makes no sense logic-wise, as the series contain nothing.

I have explained the missing pointer error already above. Your function expects a series for the second parameters, not a var.

var GSMOOTH(var price_,vars arr,var alfa)

The second parameter is series. right?

So The caller passes series ma[0].

I tried this new code but it is still wrong.

ma = series(GSMOOTH(Close[0],series(ma),Slowalfa[0]));

You now managed to pass not a series, but a series of series, if such an object existed.

How do you pass a series to a function?

Have you done the workshops? Series are used in workshop 4.