What are practical uses for STL's 'partial_sum'?

Question

What/where are the practical uses of the partial_sum algorithm in STL?

What are some other interesting/non-trivial examples or use-cases?

Answer 1

You could build a "moving sum" (precursor to a moving average):

template 
void moving_sum (const vector& in, int num, vector& out)
{
    // cummulative sum
    partial_sum (in.begin(), in.end(), out.begin());

    // shift and subtract
    int j;
    for (int i = out.size() - 1; i >= 0; i--) {
        j = i - num;
        if (j >= 0)
            out[i] -= out[j];
    }    
}

And then call it with:

vector v(10);
// fill in v
vector v2 (v.size());
moving_sum (v, 3, v2);