Dynamic SUM function needed

[snurrepang]

Hello

I'm currently trying to make a Excel sheet calculating the Silver-Meal algorithm. As a part of that I need a SUM function that sums a dynamic range of cells depending on a binary input in a third cell, and this is where I get stuck.
As in the example below, B colum sums the values in A column until there is a "1" (or any other binary value) in C column, then i starts over again.
I have tried to solve this using combinations of IF and SUM formulas without any success. Does anyone have a solution for this problem? Thanks


...A B C
1|0 0 0
2|2 2 0
3|3 5 1
4|2 2 0
5|4 6 0
6|3 9 1

PS. I anyone have experience in calculating Silver-Meal in Excel without VBA programming, please feel free to contact me. DS.