Student Portfolios

5° BEGINNING COMPUTERS
STUDENT	PORTFOLIO ADDRESS	[YT]
Christian Alsip	http://christiansportfolio1.blogspot.com/	[-]
Robbie Angel	https://drloserisaloser.blogspot.com/	[-]
Gavin Ayers	[Not Participating]	[-]
Gavin Muse	[Not Participating]	[-]
Sam Campbell	https://samuelcampbells.blogspot.com/	[-]
Saven Clemens	http://ultsaven.blogspot.com/	[-]
Autumn Creekmore	https://farmgirlcutie18.blogspot.com/	[-]
Matt Day	http://mattday11699.blogspot.com/	[-]
Tamara Edwards	https://tamaraswhateverstuff.blogspot.com/	[-]
Jacub Ellard	http://jacubellard123.blogspot.com/	[-]
Jordan Hall	https://bigjhall21.blogspot.com/	[-]
Kaylee Lambdin	http://kaylee11.blogspot.com/	[-]
Audrianna Miller	http://audrimillermasterpieces.blogspot.com/	[-]
Logan Minton	https://loganminton.blogspot.com/	[-]
Jamie Perkins	https://jamieperkinsportfolio.blogspot.com/	[-]
Sarah Phillips	http://satansdesktop.blogspot.com/	[-]
Matt Powers	[Not Participating]	[-]
Caleb Rose	http://calebrose6.blogspot.com/	[-]
Logan Smith	https://logansmith0158.blogspot.com/	[-]
Danny Taylor	https://baseballking2641.blogspot.com/	[-]
Dalton Wallen	https://kosmixpk.blogspot.com/	[-]
Riley Walp	http://rileywalp.blogspot.com/	[-]
Tessa Worley	https://tessaworley.blogspot.com/	[-]
Megan York	http://thatonehamiltonfan.blogspot.com/	[-]

Looking at Java Examples

CASE STUDY #1:  Movie Tickets

Let's look at this code for a movie ticket program:
import java.util.Scanner;
class TicketPrice {
public static void main(String args[]) {
Scanner myScanner = new Scanner(System.in);
int age;
double price = 0.00;
System.out.print("How old are you? ");
age = myScanner.nextInt();
if (age >= 12 && age < 65) {
price = 9.25;
}
if (age < 12 || age >= 65) {
price = 5.25;
}
System.out.print("Please pay $");
System.out.print(price);
System.out.print(". ");
System.out.println("Enjoy the show!");
}
}

First of all, what is the name of this Class?

• What are we bringing into the Class from Java that is already built for us?
• What does "Scanner" do?
• What does "double" mean in Java?
• What variables are we using in this code? (I see three)
• What are some of the things that are missing in this code?
• What would the ticket price be for an 8 year old?  A 14 year old?  A 66 year old?
• Draw a flow chart indicating the flow of this program.
• Next, let's update the source code:
• Begin by formatting the source code to be more readable -- add line breaks, indent (Tab) some of the lines, etc.  (See the next case study for an idea of how to format it)
• Add some comments to the code.  Remember that every Class needs a title, author(s), and version (number or dates) and maybe some comments describing what a formula or function does.

CASE STUDY #2: Divide Equally

Next let's look at this strange code for a program that will divide the total number of gumballs equally among a varied number of children:
import java.util.Scanner;

class EquallyDivide
{

    public static void main(String args[]) {
        Scanner myScanner = new Scanner(System.in);
        int gumballs;
        int kids;
        int gumballsPerKid;

        System.out.print("How many gumballs? ");

        gumballs = myScanner.nextInt();
        System.out.print("How many kids? ");

        kids = myScanner.nextInt();
        gumballsPerKid = gumballs / kids;

        System.out.print("Each kid gets ");
        System.out.print(gumballsPerKid);
        System.out.println(" gumballs.");
    }
}

So let's work with this code:
Add some comments / labels.
What is the difference between:
 System.out.println
 System.out.print
With variable names like "gumballs" or "kids" or "gumballsPerKid", this program is pretty specific.  What sorts of names could we use for variables to make this program usable for other purposes?  The "gumballs" variable might be more useful as "items", for example.  Remember, however, that you can change all instances of "gumballs" but "gumballsPerKid" is a completely different variable name.
Draw a flowchart indicating the flow of this program.
What code could we add to figure out how many gumballs are left over after they have been divided equally?

CASE STUDY #3:  Magic Cue Ball

For case number 3 we have "The Magic CueBall" -- okay, so it's ripped off... but it works... sort of:
import java.util.Scanner;
import java.util.Random;

class MagicCueBall {

    public static void main(String args[]) {
        Scanner myScanner = new Scanner(System.in);
        Random myRandom = new Random();
        int randomNumber;
        System.out.print("Type a Yes or No question: ");
        myScanner.nextLine();
        randomNumber = myRandom.nextInt(10) + 1;
        if (randomNumber > 5) {
            System.out.println("Yes. Isn’t it obvious?");
        } else {
            System.out.println("No, and don’t ask again.");
        }
    }
}

Let's do some playing with the code again:

• Again, begin by adding comments/labels to the code.
• What Java utils are we bringing in this time?
• When you run this program, how does the output text differ from the text written in the code?
• Before the "if" statement, randomNumber can be what possible numbers?  Why is there a +1 at the end of the line?
• Add some variation to the possible responses:
• 4 different "Yes" answers
• 4 different "No" answers
• 2 different "Ask Again" answers

At the beginning of the program (before asking the user to type a yes or no question), add a title text graphic.  For example:

*********************************
* Magic Cue Ball 1.0 ~ by Your Name  *
*********************************

What else could we add to make this application more usable?

CASE STUDY #4:  A Number Guessing Game -- Building a Program Step By Step

Step One: Let's try a different method for finding a random number -- this time from 1 to 1000.
public class NumberGuessingGame {
      public static void main(String[] args) {
            int secretNumber;
            secretNumber = (int) (Math.random() * 999 + 1);
            System.out.println("Secret number is " + secretNumber); // to be removed later
      }
}

Step Two: Getting a Guess (import the Scanner and reply with the guess)
import java.util.Scanner;

public class NumberGuessingGame {
      public static void main(String[] args) {
            int secretNumber;
            secretNumber = (int) (Math.random() * 999 + 1);
            System.out.println("Secret number is " + secretNumber); // to be removed
            // later
            Scanner keyboard = new Scanner(System.in);
            int guess;
            System.out.print("Enter a guess: ");
            guess = keyboard.nextInt();
            System.out.println("Your guess is " + guess);
      }
}

Step Three: Checking Your Answer

import java.util.Scanner;

public class NumberGuessingGame {
      public static void main(String[] args) {
            int secretNumber;
            secretNumber = (int) (Math.random() * 999 + 1);
            System.out.println("Secret number is " + secretNumber); // to be removed
            // later
            Scanner keyboard = new Scanner(System.in);
            int guess;
            System.out.print("Enter a guess: ");
            guess = keyboard.nextInt();
            System.out.println("Your guess is " + guess);
            if (guess == secretNumber)
                  System.out.println("Your guess is correct. Congratulations!");
            else if (guess < secretNumber)
                  System.out
                             .println("Your guess is smaller than the secret number.");
            else if (guess > secretNumber)
                  System.out
                             .println("Your guess is greater than the secret number.");
      }
}

Step Five: Add Tries.
import java.util.Scanner;

public class NumberGuessingGame {
      public static void main(String[] args) {
            int secretNumber;
            secretNumber = (int) (Math.random() * 999 + 1);
            System.out.println("Secret number is " + secretNumber); // to be removed
            // later
            Scanner keyboard = new Scanner(System.in);
            int guess;
            do {
                  System.out.print("Enter a guess: ");
                  guess = keyboard.nextInt();
                  System.out.println("Your guess is " + guess);
                  if (guess == secretNumber)
                        System.out.println("Your guess is correct. Congratulations!");
                  else if (guess < secretNumber)
                        System.out
                                   .println("Your guess is smaller than the secret number.");
                  else if (guess > secretNumber)
                        System.out
                                   .println("Your guess is greater than the secret number.");
            } while (guess != secretNumber);
      }
}

Step Six: Remove the Debug Script.
import java.util.Scanner;

public class NumberGuessingGame {
      public static void main(String[] args) {
            int secretNumber;
            secretNumber = (int) (Math.random() * 999 + 1);         
            Scanner keyboard = new Scanner(System.in);
            int guess;
            do {
                  System.out.print("Enter a guess (1-1000): ");
                  guess = keyboard.nextInt();
                  if (guess == secretNumber)
                        System.out.println("Your guess is correct. Congratulations!");
                  else if (guess < secretNumber)
                        System.out
                                   .println("Your guess is smaller than the secret number.");
                  else if (guess > secretNumber)
                        System.out
                                   .println("Your guess is greater than the secret number.");
            } while (guess != secretNumber);
      }
}

Step Seven: Suggestions for Continuing to Upgrade Your Code

• Add comments and labels [obviously]
• Create a little title text graphic to display at the beginning of your program.
• Display "Guess #" in front of [or behind] each "Enter a guess" prompt.
• Limit the number of guesses a user gets -- and you might even have it display something like "Guess 3 of 10".

Pseudocoding, Variables and Flowcharting: Flipping a Coin

A simple task like flipping a coin is a good start in pseudocoding and flow charting.

Beginning Pseudocode:

Pseudocode is just like writing out what you want your computer program to do.  A simple program (flipping a coin, for example) might look something like this:

1. Print the title on the screen (“Heads or Tails Game”)
2. Ask the user, “Heads or Tails?”
3. Flip the coin (get a random number -- either 0 or 1 with 0 being heads)
4. Tell the user what the toss was
5. Tell the user “You win!” or “You lose!”
6. Say “Thank you for playing!”

Now, where would you put extra instructions that asked, “Do you want to play again?”  What about adding a score counter?  What if you wanted to display a picture of a Head or Tail?  Pseudocode is really that easy.

Looking at Programming:

If we look at a more extensive example, this one is interesting because it tallies up the number of heads and tails we get out of 100 coin flips.  This code involves using a counter, a Math.random number generator (0 or 1 is the result), a counter for the results of each of the sides of the coin, and a "do while" loop.  Study the code and see if you can figure out what the code pieces are doing.

class Toss {
        public final int HEADS = 0;
        static int countH = 0;
        static int countT = 0;
        static int counter = 0;
        private static int face;

        public static void flip() {
                face = (int) (Math.random() * 2);
        }

        public String toString() {
                String faceName;
                counter++;
                if (face == HEADS) {
                        faceName = "Heads";
                        countH++;
                } else {
                        faceName = "Tails";
                        countT++;
                }
                return faceName;
        }

        public static void main(String[] args) {
                System.out.println("Outcomes:");
                do {
                        flip();
                        System.out.println(new Toss().toString());
                } while (counter < 100);
                System.out.println("Number of Tails: " + countT);
                System.out.println("Number of Heads: " + countH);
        }
}