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

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

@@ -0,0 +1,23 @@
+package com.thealgorithms.maths;
+
+public class PowRecursion {
+
+    public static void main(String[] args) {
+        assert Double.compare(pow(2, 0), Math.pow(2, 0)) == 0;
+        assert Double.compare(pow(0, 2), Math.pow(0, 2)) == 0;
+        assert Double.compare(pow(2, 10), Math.pow(2, 10)) == 0;
+        assert Double.compare(pow(10, 2), Math.pow(10, 2)) == 0;
+    }
+
+    /**
+     * Returns the value of the first argument raised to the power of the second
+     * argument
+     *
+     * @param a the base.
+     * @param b the exponent.
+     * @return the value {@code a}<sup>{@code b}</sup>.
+     */
+    public static long pow(int a, int b) {
+        return b == 0 ? 1 : a * pow(a, b - 1);
+    }
+}