Why I receive an unknown variable error in my function?

Question

I'm using AlgoBuild and inside the "input_vet()" function there's a while loop and in its condition I recall the variable N, which I assign a value in the main, and shows a unknown variable error. The problem asks me to choose the dimension of the array (N), sort it, and I have to find the max number, the arithmetic average. I can't get over this error but I know how to find the other answers to the problem

Answer 1

I found the solution if someone is interested. It was a problem of formal parameters and current parameters. I had to write and recall the function in a different way. I leave here the photo of an exercise I did to solve the problem.