Lame addition/sum problem

Okay, so I am working on this program, and have been for a while now. I have the line of code:

This code works and does what it is intended to. However, I added a button to add more elements to the array, but I still need this total.

My question is how do I total elements in an array without knowing how many elements I will have? I ask this because the button allows the user to add 0 - ? additional elements. So it will be "unknown".

Can anybody help?

The number of elements in an array can always be accessed with the length member variable

Thank you so much, that helped a lot. All I came up with on my own was

Which worked for the elements that were already written in the code, but when I added new elements it would not re-total the elements, but your example worked perfectly. Thank you again!