Change project structure to a Maven Java project + Refactor (#2816)

src/main/java/com/thealgorithms/maths/Average.java

@@ -0,0 +1,46 @@
+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);
+    }
+}