Adding array elements?

Question

C++ / C#

Hello, how can I add array elements, for example, from 2 to 4 At the same time, the number with index 2 is not
taken into account in the sum, but 4 is taken into account 10,13,4,-8];

Answer 1

In this case, the number with index 2 is not taken into account in the amount, and 4 is taken into account

That is, from 3 to 4 inclusive.

var numbers = [1,-3,5,-6,-10,13,4,-8];
var sum = numbers[3..4].Sum();