Adding the comments for the early CS's

CS4 - Challenge Solution/Main.java

@@ -1,23 +1,42 @@
 import java.util.Scanner;
 
+/*
+    CS4 Challenge Solution
+
+    Original Challenge Description: Built a program that requests the user's age, 
+        and return on of the following:
+            <= 18 - You're a youngin'
+            > 18 AND <= 35 - The early adult years
+            > 35 AND <= 55 - Middle aged, time to buy a really expensive car
+            > 55 AND <= 64 - Getting old...
+            > 64 - Retirement! Time to live out the golden years. 
+*/
 public class Main {
     public static void main(String[] args) {
+        //Start with setting up System.in through a Scanner
         Scanner scan = new Scanner(System.in);
 
+        //Request the user's age, as an int
         System.out.print("Enter your age: ");
         int age = scan.nextInt();
 
+        //Close the scanner, because good practice
         scan.close();
 
-        if(age <= 18) {
+        //This is a larger if statement than what we saw in the demos and for good reason. 
+        //We cover all the different case scenarios here as described in the challenge, but
+        //notice how I didn't explicitly put an else if statement for > 64 years old condition.
+        //Because it's the last condition, and we have if's or else if's for the other possible
+        //conditions, we can put the last possible condition as the "else" statement. 
+        if(age <= 18) { // <= 18
             System.out.println("You're a youngin'");
-        } else if(age > 18 && age <= 35) {
+        } else if(age > 18 && age <= 35) { // > 18 AND <= 35
             System.out.println("The early adult years");
-        } else if(age > 35 && age <= 55) {
+        } else if(age > 35 && age <= 55) { // > 35 AND <= 55
             System.out.println("Middle aged, time to buy a really expensive car");
-        } else if(age > 55 && age <= 64) {
+        } else if(age > 55 && age <= 64) { // > 55 AND <= 64
             System.out.println("Getting old...");
-        } else {
+        } else { // > 64
             System.out.println("Retirement! Time to live out the golden years.");
         }
     }