Average of an Array

/*
 * Problem : Calculate the average of the elements of an array.
 * Input   : First line is n (number of elements). Second line has n integers.
 * Output  : The average with 2 digits after the decimal point, or "Array is empty".
 * Approach: Add all elements, then divide the sum by the count using decimal division.
 * Time    : O(n)
 * Space   : O(1)
 * Java    : 8 or newer.
 */
import java.util.Locale;
import java.util.Scanner;

public class Main {
    // This method receives an array and returns its average as a decimal number.
    static double average(int[] array) {
        // Step 1: Use a long for the sum, because many large int values can overflow an int.
        long sum = 0;

        // Step 2: Visit every element of the array and add it to the sum.
        for (int element : array) {
            sum = sum + element;
        }

        // Step 3: Divide as decimal numbers. Integer division would drop the decimal part.
        // Example: 28 / 5 = 5 with integers, but 28.0 / 5 = 5.6 with decimals.
        return (double) sum / array.length;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int count = scanner.nextInt();

        // Edge case: an empty array has no average, so we stop here.
        if (count == 0) {
            System.out.println("Array is empty");
            return;
        }

        int[] array = new int[count];
        for (int i = 0; i < count; i++) {
            array[i] = scanner.nextInt();
        }

        // Locale.US makes sure the decimal separator is a dot on every computer.
        System.out.println(String.format(Locale.US, "%.2f", average(array)));
    }
}