What function cum() in pine script is?

External question — Stack Overflow Stack Exchange Author: FernandoJ26 Original post: https://stackoverflow.com/questions/63055580 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I'm trying to understand cum() function on pine script, is there another way to code the same thing without using cum function? I'm trying to get similar code in mql4, but I only need to understand what cum does with an example code.