finished exercise 33

Author: Jonathan-Birkey

src/com/github/jonathanbirkey/chapter05/Exercise33.java

@@ -2,14 +2,26 @@
  * @author : Jonathan Birkey
  * @mailto : [email protected]
  * @created : 28Feb2024
- *     <p>(Display leap years) Write a program that displays all the leap years, 10 per line, from
- *     101 to 2100, separated by exactly one space. Also display the number of leap years in this
- *     period.
+ *     <p>(Perfect number) A positive integer is called a perfect number if it is equal to the sum
+ *     of all of its positive divisors, excluding itself. For example, 6 is the first perfect number
+ *     because 6 = 3 + 2 + 1. The next is 28 = 14 + 7 + 4 + 2 + 1. There are four perfect numbers <
+ *     10,000. Write a program to find all these four numbers.
  */
 package com.github.jonathanbirkey.chapter05;
 
 public class Exercise33 {
   public static void main(String[] args) {
-    // TODO: solve
+
+    for (int i = 1; i < 10000; i++) {
+      int sumPosDivisors = 0;
+      for (int j = 1; j <= (int) i / 2; j++) {
+        if (i % j == 0) {
+          sumPosDivisors += j;
+        }
+      }
+      if (i == sumPosDivisors) {
+        System.out.printf("Perfect number: %d\n", i);
+      }
+    }
   }
 }