Additive Persistence

ardallie · ardallie · commit 76b49c71b72c · 2021-08-09T21:46:24.000+01:00
diff --git a/src/easy/AdditivePersistence.java b/src/easy/AdditivePersistence.java
@@ -0,0 +1,48 @@
+package easy;
+
+/**
+ * Have the function AdditivePersistence(num) take the num parameter being passed
+ * which will always be a positive integer
+ * and return its additive persistence which is the number of times
+ * you must add the digits in num until you reach a single digit.
+ * ---
+ * For example: if num is 2718 then your program
+ * should return 2 because 2 + 7 + 1 + 8 = 18
+ * and 1 + 8 = 9, and you stop at 9.
+ */
+public class AdditivePersistence {
+
+  /**
+   * Additive Persistence function.
+   *
+   * @param num input number
+   * @return additive persistence which is the number of times
+   */
+  private static int additivePersistence(int num) {
+    int times = 0;
+    int added = num;
+    while (added > 9) {
+      int sum = 0;
+      String[] intArr = Integer.toString(added).split("");
+      for (String i : intArr) {
+        sum += Integer.parseInt(i);
+      }
+      added = sum;
+      times++;
+    }
+    return times;
+  }
+
+  /**
+   * Entry point.
+   *
+   * @param args command line arguments
+   */
+  public static void main(String[] args) {
+    var result1 = additivePersistence(199);
+    System.out.println(result1);
+    var result2 = additivePersistence(913);
+    System.out.println(result2);
+  }
+
+}
