From f432c0f5840d1151e4b4491abc55303e8dc8d4d9 Mon Sep 17 00:00:00 2001
From: Krishna Vedala <krishna.vedala@ieee.org>
Date: Wed, 27 May 2020 16:22:10 -0400
Subject: [PATCH] documetnation for positive divisors

---
 math/number_of_positive_divisors.cpp | 46 ++++++++++++++++------------
 1 file changed, 27 insertions(+), 19 deletions(-)

diff --git a/math/number_of_positive_divisors.cpp b/math/number_of_positive_divisors.cpp
index 48ab63c36..f157f7b41 100644
--- a/math/number_of_positive_divisors.cpp
+++ b/math/number_of_positive_divisors.cpp
@@ -1,34 +1,39 @@
-/// C++ Program to calculate number of divisors.
-
-#include<iostream>
-#include<vector>
-
 /**
+ * @file
+ * @brief C++ Program to calculate number of divisors
+ *
  * This algorithm use the prime factorization approach.
  * Any number can be written in multiplication of its prime factors.
- * Let N = P1^E1 * P2^E2 ... Pk^Ek
- * Therefore. number-of-divisors(N) = (E1+1) * (E2+1) ... (Ek+1).
- * Where P1, P2 ... Pk are prime factors and E1, E2 ... Ek are exponents respectively.
+ * <br/>Let N = P1^E1 * P2^E2 ... Pk^Ek
+ * <br/>Therefore. number-of-divisors(N) = (E1+1) * (E2+1) ... (Ek+1).
+ * <br/>Where P1, P2 ... Pk are prime factors and E1, E2 ... Ek are exponents
+respectively.
  *
  * Example:-
- * N = 36
- * 36 = (3^2 * 2^2)
- * number_of_positive_divisors(36) = (2+1) * (2+1) = 9.
- * list of positive divisors of 36 = 1, 2, 3, 4, 6, 9, 12, 18, 36.
+ * <br/>N = 36
+ * <br/>36 = (3^2 * 2^2)
+ * <br/>number_of_positive_divisors(36) = (2+1) * (2+1) = 9.
+ * <br/>list of positive divisors of 36 = 1, 2, 3, 4, 6, 9, 12, 18, 36.
  *
  * Similarly if N is -36 at that time number of positive divisors remain same.
  *
  * Example:-
- * N = -36
- * -36 = -1 * (3^2 * 2^2)
- * number_of_positive_divisors(-36) = (2+1) * (2+1) = 9.
- * list of positive divisors of -36 = 1, 2, 3, 4, 6, 9, 12, 18, 36.
+ * <br/>N = -36
+ * <br/>-36 = -1 * (3^2 * 2^2)
+ * <br/>number_of_positive_divisors(-36) = (2+1) * (2+1) = 9.
+ * <br/>list of positive divisors of -36 = 1, 2, 3, 4, 6, 9, 12, 18, 36.
  *
 **/
 
+#include <iostream>
+#include <vector>
+
+/**
+ * Algorithm
+ */
 int number_of_positive_divisors(int n) {
     std::vector<int> prime_exponent_count;
-    for (int i=2; i*i <= n; i++) {
+    for (int i = 2; i * i <= n; i++) {
         int prime_count = 0;
         while (n % i == 0) {
             prime_count += 1;
@@ -44,13 +49,16 @@ int number_of_positive_divisors(int n) {
 
     int divisors_count = 1;
 
-    for (int i=0; i < prime_exponent_count.size(); i++) {
-        divisors_count = divisors_count * (prime_exponent_count[i]+1);
+    for (int i = 0; i < prime_exponent_count.size(); i++) {
+        divisors_count = divisors_count * (prime_exponent_count[i] + 1);
     }
 
     return divisors_count;
 }
 
+/**
+ * Main function
+ */
 int main() {
     int n;
     std::cin >> n;