Merge branch 'main' into comments

CS2 - Challenge Solution/Main.java

@@ -1,12 +1,23 @@
 import java.util.Scanner;
 
+/*
+    CS2 Challenge Solution
+
+    Original Challenge Description: Build a program that requests a user's name,
+    and then prints a greeting. 
+*/
 public class Main {
     public static void main(String[] args) {
+        //Setup a Scanner to work with System.in
         Scanner scan = new Scanner(System.in);
 
+        //Start by printing some text that will prompt the user to enter a name
+        //then print another line that Says "Hello" and then whatever the user entered.
         System.out.print("Please enter your name: ");
         System.out.println("Hello " + scan.nextLine());
 
+        //Close the scanner, while not really necessary, it's a good habit to get into
+        //for other resources. 
         scan.close();
     }
 }

CS3 - Challenge Solution/Main.java

@@ -1,9 +1,18 @@
 import java.util.Scanner;
 
+/*
+    CS3 Challenge Solution
+
+    Original Challenge Description: Build a program that requests
+    three numbers from the user, and performs a math operation on 
+    them and prints the result. 
+*/
 public class Main {
     public static void main(String[] args) {
+        //Start with setting up System.in through a Scanner
         Scanner scan = new Scanner(System.in);
 
+        //Grab three values from the user, all of them are doubles
         System.out.print("Value 1: ");
         double firstValue = scan.nextDouble();
 
@@ -13,8 +22,17 @@ public class Main {
         System.out.print("Value 3: ");
         double thirdValue = scan.nextDouble();
 
+        //Print out the operation being performed. Two things of note here, 
+        //the first thing in the println is an empty string, this helps Java to know
+        //that it's supposed to be combining Strings, not attempting to do regular
+        //mathematical addition.
+        //The second thing is that we have the actual math at the end of the println
+        //statement wrapped in parenthesis. This helps to ensure that Java treats 
+        //that as a math operation, and separates it from all of the combining of Strings
+        //that is going on outside the parenthesis. 
         System.out.println("" + firstValue + " / " + secondValue + " - " + thirdValue + " = " + (firstValue / secondValue - thirdValue));
 
+        //Close the scanner, because good practice. 
         scan.close();
     }
 }

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.");
         }
     }

CS5 - Challenge Solution/Main.java

@@ -1,26 +1,51 @@
 import java.util.Random;
 import java.util.Scanner;
 
+/*
+    CS5 Challenge Solution
+
+    Original Challenge Description: Write a program that requests an integer
+    from the user, and prints that many random numbers AND prints the sum 
+    and average of those numbers. 
+*/
 public class Main {
     public static void main(String[] args) {
+        //Setup our random number generator and a scanner
+        //to get input from the user
         Random random = new Random();
         Scanner scan = new Scanner(System.in);
 
+        //Get the number of random numbers the user 
+        //wants us to generate
         System.out.print("Number of random values to create: ");
         int numberToRandomize = scan.nextInt();
 
+        //Close the scanner, we shouldn't need it anymore. 
         scan.close();
 
+        //Create a variable to store the sum of all the numbers
+        //we're about to generate. Notice that it is a DOUBLE,
+        //not an int
         double sum = 0;
 
+        //Setup a for loop, this loop will run for the number
+        //of random numbers the user requested. 
         for(int i = 0; i < numberToRandomize; i++) {
+            //Generate a random number and store it temporarily
             double randomNumber = random.nextDouble();
 
+            //Properly print the current random number (i + 1), 
+            //along with the number that we actually generated
             System.out.println("Random Number " + (i + 1) + ": " + randomNumber);
 
+            //Add the current random number to the sum. 
+            //sum += randomNumber is equivalent to sum = sum + randomNumber
             sum += randomNumber;
         }
 
+        //Print the sum, and then print the average. 
+        //The average being the sum divided by the number of numbers
+        //to randomize requested by the user. 
         System.out.println("Sum = " + sum);
         System.out.println("Average = " + (sum / numberToRandomize));
     }

CS6 - Challenge Solution/Main.java

@@ -1,19 +1,45 @@
 import java.util.Random;
 import java.util.Scanner;
 
+/*
+    CS6 Challenge Solution
+
+    Original Challenge Description: Write a program that generates
+    a random number, and repeatedly asks the user to guess the number,
+    telling them if they're too low, too high, of if they guess correctly.
+    The program should end once they guess the correct number. 
+*/
 public class Main {
     public static void main(String[] args) {
+        //Setup our random number generator and a scanner
+        //to get input from the user
         Random random = new Random();
         Scanner scan = new Scanner(System.in);
 
+        //Generate a random integer 0-100 (inclusive)
         int randomValue = random.nextInt(101);
 
+        //Create a value for guess and set it to something that
+        //definitely isn't going to be the random number we just
+        //generated. We do this because the while loop that we are
+        //going to use needs to run so long as the guess does not
+        //equal the random value we generated. If it's something
+        //we know isn't possible for the random number, then
+        //we know our loop will run properly at least once. 
         int guess = -1;
 
+        //While the user hasn't guessed the right number
         while(randomValue != guess) {
+            //Ask the user for a number, and overwrite
+            //the value of guess with that number
             System.out.print("Guess the number: ");
             guess = scan.nextInt();
 
+            //This if statement just checks to see if the user's guess
+            //is less, more or the same as what the random generated
+            //number was. If the guess is the same as the random number
+            //the condition of the while loop will handle getting out
+            //of the loop, so no need to call break. 
             if(guess < randomValue) {
                 System.out.println("You're too low");
             } else if(guess > randomValue) {
@@ -23,6 +49,7 @@ public class Main {
             }
         }
 
+        //Close our scanner, for good measure
         scan.close();
     }
 }

CS7 - Challenge Solution/Ball.java

@@ -1,30 +1,52 @@
+//A class based representation of a ball
 public class Ball {
+    //3 instance variables, the first, diameter,
+    //stores the diameter of the ball in whatever
+    //units you want.
+    //The second, a String representation of the color
+    //of the ball.
+    //The third, an integer that stores the number
+    //of times the ball has been bounced. 
     private double diameter;
     private String color;
     private int timesBounced;
 
+    //Constructor to create balls with, specifying 
+    //the diameter and color of the ball. 
+    //Note that timesBounced is set to 0, 
+    //this constructor assumes that this is a fresh
+    //ball that has never been bounced.
     public Ball(double newDiameter, String newColor) {
         diameter = newDiameter;
         color = newColor;
         timesBounced = 0;
     }
 
+    //Returns the current diameter of the ball
     public double getDiameter() {
         return diameter;
     }
 
+    //Returns the current color of the ball
     public String getColor() {
         return color;
     }
 
+    //Returns the number of times this ball has
+    //been bounced
     public int getTimesBounced() {
         return timesBounced;
     }
 
+    //Bounces the ball, all this does is add
+    //one to the timesBounced instance variable
     public void bounceBall() {
         timesBounced++;
     }
 
+    //A normal toString method, that provides the 
+    //instance information about the Ball that we
+    //are currently working with as a String
     public String toString() {
         return "This ball is " + color + " with a diameter of " +
             diameter + " and has been bounced " + timesBounced + 

CS7 - Challenge Solution/Main.java

@@ -1,14 +1,45 @@
+/*
+    CS7 Challenge Solution
+
+    Original Challenge Description: 
+
+    Write a class Ball with the following:
+        Characteristics
+            diameter (double)
+            color (string)
+            timesBounced (int)
+        Behaviors
+            bounceBall
+            getDiameter
+            getColor
+            getTimesBounced
+    Create 2 Balls
+        Ball 1
+            Diameter: 5
+            Color: Red
+            Bounce the ball 10 times
+        Ball 2
+            Diameter: 1
+            Color: Yellow
+            Bounce the ball 1 time
+        Print all the values for both balls
+*/
 public class Main {
     public static void main(String[] args) {
+        //Create two balls, one 5 units in diameter and red,
+        //and another that's one unit in diameter and yellow
         Ball ball1 = new Ball(5, "Red");
         Ball ball2 = new Ball(1, "Yellow");
 
+        //Using a for loop, bounce ball1 10 times
         for(int i = 0; i < 10; i++) {
             ball1.bounceBall();
         }
 
+        //Bounce ball2 once
         ball2.bounceBall();
 
+        //Print information about both ball1 and ball2
         System.out.println(ball1);
         System.out.println(ball2);
     }