What is the output of the following code? // before’s elements set to: 0, 4, 8, then 12 after. at(0) = before. at(0); for(i = 1; i < before. size(); ++i) { tmp = before. at(i-1) + before. at(i); after. at(i) = tmp / 2; cout < < after. at(i) < < " "; }