How to convert int array to int?

Question

What I would like to learn how to do is to convert an int array to an int in C#.

However I want to append the int with the values from the array.

Example:

Answer 1

int result = 0;
int[] arr = { 1, 2, 3, 4};
int multipicator = 1;
for (int i = arr.Length - 1; i >= 0; i--)
{
   result += arr[i] * multipicator;
   multipicator *= 10;
}