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 can use it to generate a monotonically increasing sequence of numbers. For example, the following generates a vector containing the numbers 1 through 42:

std::vector v(42, 1);
std::partial_sum(v.begin(), v.end(), v.begin());

Is this an everyday use case? Probably not, though I've found it useful on several occasions.

You can also use std::partial_sum to generate a list of factorials. (This is even less useful, though, since the number of factorials that can be represented by a typical integer data type is quite limited. It is fun, though :-D)

std::vector v(10, 1);
std::partial_sum(v.begin(), v.end(), v.begin());
std::partial_sum(v.begin(), v.end(), v.begin(), std::multiplies());