As Varun Sareen Sugested in the second answer the easier way would be to add the numbers as they are gotten. Something like (mine is in VB)
Dim ItemToAdd As Integer
For Each DataItem In SomeCollection
ItemToAdd = ItemToAdd + DataItem
Total.text = ItemToAdd.ToString
Next
Perhaps Varun Sareen Can Show you the "C" version if that is what you need
hope this helps.