Lab 08

Recap: Lab (Github) Workflow 🔄 - How to Work on Labs

Follow these steps for every lab carefully to access, complete, and submit your assignment.

1. Accept the Assignment

   • Open the Lab Assignment Link the professor provided.
   • Click "Accept the assignment". This will create your personal assignment repository on GitHub under the OOP-Fall-2025 organization.
   • You'll be taken to your repository page. Verify that the URL looks like github.com/OOP-Fall-2025/lab-number-yourusername.

2. Clone the Repository to Your Computer

   • On your repository page, click the blue <> Code button.
   • In the dropdown menu, choose "Open with GitHub Desktop".
   • GitHub Desktop will launch. Choose a preferred local folder on your computer to save the project and click "Clone".
   • If asked "How are you planning on using this fork?", select "For my own purpose" and continue.

3. Open in VS Code and Start Coding

   • In GitHub Desktop, ensure the "Current repository" is the one for this lab.
   • Click the "Open in Visual Studio Code" button.
   • VS Code will open the project folder. You can now begin writing your solutions in the Lab08.java file.

4. Save and Submit Your Work

   • Commit (Save) Changes: As you work, save your file in VS Code (Ctrl+S or Cmd+S). To record your progress, go to the Source Control tab (the fork icon) on the left sidebar in VS Code. Type a descriptive message in the message box (e.g., "Finished Task 1 and 2") and click "Commit". You must enter a message.
   • Push (Submit) to GitHub: When you are finished with the lab or want to back up your work, go back to GitHub Desktop. Click the "Push origin" button at the top of the window. This sends your committed changes from your computer to your GitHub repository online.

5. Verify Your Submission

   • After you push, you can click "View on GitHub" in GitHub Desktop to open your repository in the browser.
   • On the GitHub website, make sure you are viewing the main branch and confirm that all of your latest code is visible.

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Lab 08 Tasks

Shapeshifting

Same contract, different performances

Task 1: Animal Kingdom

Topics Covered: Interfaces, Overriding, Overloading

What This Task Practices: You'll create animals that can speak using an interface, override their behaviors, and use overloaded constructors to create objects in different ways.

You will create 1 interface and 3 classes:

Speakable (Interface)

• Create an interface called Speakable
• Add one method signature: void makeSound()

Animal

• This is the base class
• Implements the Speakable interface
• Property: name (String) - The name of the animal
• Property: age (int) - The age of the animal
• Overloaded Constructor #1: Takes only name as parameter, sets name and sets age to 0
• Overloaded Constructor #2: Takes name and age as parameters, sets both properties
• Method: toString() that returns the string "[name] is an animal!"
  • Use @Override on the toString() method
• Method: makeSound() that prints "[name] makes a sound!"
  • Use @Override on the makeSound() method

Duck

• Inherits from Animal and implements Speakable (inherited from Animal)
• Overloaded Constructor #1: Takes only name, calls super(name)
• Overloaded Constructor #2: Takes name and age, calls super(name, age)
• Override toString() to return the string "[name] is a duck!"
• Override makeSound() to print "[name] quacks!"

Sloth

• Inherits from Animal and implements Speakable (inherited from Animal)
• Overloaded Constructor #1: Takes only name, calls super(name)
• Overloaded Constructor #2: Takes name and age, calls super(name, age)
• Override toString() to return the string "[name] is a sloth!"
• Override makeSound() to print "[name] moves slowly and says nothing."

Main

• Ask for the Duck's name
• Create a Duck object using the constructor with just name
• Ask for the Sloth's name and age
• Create a Sloth object using the constructor with name and age
• Print the Duck object (tests toString override)
• Call makeSound() on the Duck (tests interface implementation)
• Print the Sloth object (tests toString override)
• Call makeSound() on the Sloth (tests interface implementation)

Example Output

Duck Name: Quackers

Sloth Name: Velcro

Sloth Age: 5

Quackers is a duck!

Quackers quacks!

Velcro is a sloth!

Velcro moves slowly and says nothing.

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(There's more...)

Everyone plays their part

Task 2: Rock and Roll All Night

Topics Covered: Interfaces, Polymorphism, Overriding, Overloading, Inheritance

What This Task Practices: You'll build a band where different musicians inherit from a base class, implement a performer interface, and demonstrate polymorphism by storing different types of musicians in one array.

You will create 1 interface and 7 classes.

Performer (Interface)

• Create an interface called Performer
• Add one method signature: void perform()

Musician

• Implements the Performer interface
• Public property: name (String) - The name of the musician
• Overloaded Method #1: play() - Returns "[name] plays music."
• Overloaded Method #2: play(String song) - Returns "[name] plays [song]."
• Method: perform() - Prints "[name] is performing!"
  • Use @Override on the perform() method

Bassist

• Inherits from Musician
• Override play() to return: "[name] plays bass."

Drummer

• Inherits from Musician
• Override play() to return: "[name] plays drums."

Guitarist

• Inherits from Musician
• Override play() to return: "[name] plays guitar."

RhythmGuitarist

• Inherits from Guitarist
• Override play() to return: "[name] plays rhythm."

LeadGuitarist

• Inherits from Guitarist
• Override play() to return: "[name] plays a mean solo!"

Main

• Create an array of Musician (size 4)
• For each Musician, ask the name and kind of musician (Bassist, Drummer, RhythmGuitarist, LeadGuitarist)
• Create the appropriate type of Musician and set the name

After you have the band...

• Loop through the band
• Print: band[i].play() (demonstrates polymorphism and overriding)
• Call: band[i].perform() (demonstrates interface implementation)

Example Output

Name: Ringo

Kind: Drummer

Name: Paul

Kind: Bassist

Name: George

Kind: RhythmGuitarist

Name: John

Kind: LeadGuitarist

Ringo plays drums.

Ringo is performing!

Paul plays bass.

Paul is performing!

George plays rhythm.

George is performing!

John plays a mean solo!

John is performing!

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Key Concepts Practiced:

• Interfaces: Creating and implementing contracts (Speakable, Performer)
• Overriding: Using @Override to change parent class behavior
• Overloading: Multiple constructors/methods with different parameters
• Polymorphism: Using parent class references to hold child objects

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Need Help?

Ask me for help! I'm literally in the same room as you!

Finished?

When you are done with the labs (finished and committed on GitHub properly), call me over and show me. Tell me your name and I'll mark you as done!