MetaPost variables used as labels

Dear colleagues,

I have the following question concerning MetaPost. If
I have a numeric variable defined in a MetaPost file
is it possible to use its value as a label? For
examle:
n := 5;
pair p;
p := (100,100);
label(value_of_n, p);

or more complex:
n := 5;
pair p[];
for i=0 upto n-1:
  p[i] := (i+1)*(100,100);
  label(value_of_i, p[i]);
endfor;

I am interesting in it because some of my labels
follow some rules that can be described in a for
clause and this will save me the manual labeling of
each point (I had about 50 labels in my last figure).
I read carefully "Integrating Text and Graphics" from
John Hobby's manual and other docs too, but didn't fnd
it.
I will appreciate any help.
Regards 
Ivan Ivanov
Department of Mathematcis and Computer Science
Sofia University

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