How does one read in files with incremental names?

I have

for i from 1 to 10 do
   a||i:=readdata(`c:/test/i.txt`,string,7): 
end do:

I don't know how to escape the i out of the quotes so it can be used in the loop. 

How can I build an increasing list using a loop?

Something like this

a[1]:= [...]
a[2]:= [...]
a[3]:= [...]

c[1]:=a[1]
c[2]:=[op(a[1]),op(a[2])]
c[3]:=[op(a[1]),op(a[2]),op(a[3])]

etc...

I thought about using a loop but then got stuck

for i from 1 to 3 do
  c[i]:= ???

Just a simple histogram, but how do I select the values from the graph. 

op(b) pulls out the data of the graph

POLYGONS([[1., 0], [2., 0], [2., 1], [1., 1]], [[2., 0], [3., 0], [3., 0], [2., 0]], [[3., 0], [4., 0], [4., 1], [3., 1]], [[4., 0], [5., 0], [5., 2], [4., 2]], [[5., 0], [6., 0], [6., 1], [5., 1]], [[6., 0], [7., 0], [7., 1], [6., 1]], [[7., 0], [8., 0], [8., 1], [7., 1]], [[8., 0], [9., 0], [9., 4], [8., 4]], COLOUR(HSV, .5476190475, 1.000000000, .7000000000))

In all versions prior to and including Maple 13 the Histogram default incorrectly displays the data.  Has this been fixed in 14?

eg.

a:=[1,2,3,4,5,6,7,8,9,8,9,7,6,5,4,2,2]

with(Statistics):
Histogram(a,frequencyscale=absolute,binwidth=1)

Clearly the...

How can I animate a plot into another plot?

For example x^2   into  x^3. 
I know this doesn't work but I mean something like this   animate(plot,[x,x=x^2..x^3])