Excel for loop to get value from another row - excel

Question

I have an spreadsheet that contains various data. It looks like this:
A A A B B C C C C
a 1 2 3 2 1 4 2 3 2
b 0 2 3 3 0 1 2 3 0
c 6 6 3 0 2 1 0 4 0
etc.
What I want is to add all the Aa's and come up with a Aa total, all the Bb's and come up with a Bb total, all the Ab's etc.
What I want to do is, for every column, check if it is A, B or C. I want to do that because the data may change I might end up with four columns for A, two for B, etc. I know however that a, b and c will stay where they are.
I also don't know the order of A, B and C. There could be two A's followed by two C's and then one B.
My final result will be a table containing all the totals:
Aa Ab Ac
Ba Bb Bc
Ca Cb Cc
Where in the previous example would mean that Aa = 1 + 2 + 3 = 6, Ab = 5, etc.
Something like that.
I think the way to go is for 1-1 (the total of Aa's) is to go through every column in the first row. Check if it is an A. If it is, then get the value of the same column but second row. Add it to the total. When gone through all the columns, show up the total in 1-1.
What I have so far (for A):
Sub getA()
Dim x As Integer
Dim total As Integer
'cols = Find number of columns with data in them
For x = 1 To cols
'cell = cell in Ax
If InStr(1, cellvalue, "a") = 1 Then
'val = value from row 5 in same column
total = total + Val
End If
Next
End Sub
But I don't really know how to proceed with the commented lines.
Finally, another thing I would like to know is how will these values be presented in their respective cells without any extra event being carried (button for example). They should just appear in their cells from the moment someone opens the spreadsheet.
Any help is greatly appreciated.
Thanks.

Answer 1

Just an FYI, this can be done using the SUMPRODUCT formula:
=SUMPRODUCT(($B$1:$J$1=D$9)*($A$2:$A$4=$C10)*$B$2:$J$4)
EDIT
To compare the first letter then use this formula:
=SUMPRODUCT((LEFT($B$1:$J$1,1)=D$9)*($A$2:$A$4=$C10)*$B$2:$J$4)

Answer 2

Are you looking for something like:
Function countletter(strLetter As String) As Double
Dim x As Double, y As Double, xMax As Double, yMax As Double
xMax = Range("A1").CurrentRegion.Columns.Count
yMax = Range("A1").CurrentRegion.Rows.Count
For x = 1 To xMax
For y = 1 To yMax
If Cells(y, x).Value = strLetter Then
countletter = countletter + 1
End If
Next
Next
End Function