Average.java

package com.thealgorithms.maths;

/**
 * Calculate average of a list of numbers
 */
public class Average {

    private static final double SMALL_VALUE = 0.00001f;

    public static void main(String[] args) {
        assert Math.abs(average(new double[]{3, 6, 9, 12, 15, 18, 21}) - 12) < SMALL_VALUE;
        assert Math.abs(average(new double[]{5, 10, 15, 20, 25, 30, 35}) - 20) < SMALL_VALUE;
        assert Math.abs(average(new double[]{1, 2, 3, 4, 5, 6, 7, 8}) - 4.5) < SMALL_VALUE;
        int[] array = {2, 4, 10};
        assert average(array) == 5;
    }

    /**
     * Calculate average of a list of numbers
     *
     * @param numbers array to store numbers
     * @return mean of given numbers
     */
    public static double average(double[] numbers) {
        double sum = 0;
        for (double number : numbers) {
            sum += number;
        }
        return sum / numbers.length;
    }

    /**
     * find average value of int array
     *
     * @param array the array contains element and the sum does not excess long
     * value limit
     * @return average value
     */
    public static int average(int[] array) {
        long sum = 0;
        for (int i = 0; i < array.length; ++i) {
            sum += array[i];
        }
        return (int) (sum / array.length);
    }
}