Lesson 1.12

CSA Unit 1.12

Popcorn Hack #1

class Book {
    String title;
    int pages;

    void printInfo() {
        System.out.println("Title: " + title + ", Pages: " + pages);
    }
}

class MainPopcorn {
    public static void main(String[] args) {
        Book myBook = new Book();
        myBook.title = "The Java Journey";
        myBook.pages = 250;
        myBook.printInfo();
    }
}

Title: The Java Journey, Pages: 250

Check In

1. Class vs. Object: A class is a blueprint that defines the structure and behavior of something, while an object is a specific instance created from that class.

2. Reference variable: It stores the memory address (reference) of the object, not the actual object itself.

3. Common method: Every object has the toString() method (inherited from the Object class).

Homework Hack 1

public class Student {
    // Instance variables
    String name;
    int grade;
    int pets;
    int siblings;

    // Main method
    public static void main(String[] args) {
        // Create 3 student objects
        Student s1 = new Student();
        s1.name = "Ava Johnson";
        s1.grade = 10;
        s1.pets = 2;
        s1.siblings = 1;

        Student s2 = new Student();
        s2.name = "Liam Rivera";
        s2.grade = 11;
        s2.pets = 0;
        s2.siblings = 3;

        Student s3 = new Student();
        s3.name = "Noah Patel";
        s3.grade = 9;
        s3.pets = 1;
        s3.siblings = 2;

        // Print each student's information
        System.out.println(s1.name + " - Grade: " + s1.grade + ", Pets: " + s1.pets + ", Siblings: " + s1.siblings);
        System.out.println(s2.name + " - Grade: " + s2.grade + ", Pets: " + s2.pets + ", Siblings: " + s2.siblings);
        System.out.println(s3.name + " - Grade: " + s3.grade + ", Pets: " + s3.pets + ", Siblings: " + s3.siblings);
    }
}

Ava Johnson - Grade: 10, Pets: 2, Siblings: 1


Liam Rivera - Grade: 11, Pets: 0, Siblings: 3
Noah Patel - Grade: 9, Pets: 1, Siblings: 2

Homework Hack 2

public class Student {
    String name;
    int grade;
    int pets;
    int siblings;

    public static void main(String[] args) {
        // Create 3 student objects
        Student s1 = new Student();
        s1.name = "Ava Johnson";
        s1.grade = 10;
        s1.pets = 2;
        s1.siblings = 1;

        Student s2 = new Student();
        s2.name = "Liam Rivera";
        s2.grade = 11;
        s2.pets = 0;
        s2.siblings = 3;

        Student s3 = new Student();
        s3.name = "Noah Patel";
        s3.grade = 9;
        s3.pets = 1;
        s3.siblings = 2;

        // Create a reference variable (nickname) for s1
        Student nickname = s1;

        // Output instance attributes for nickname
        System.out.println("Nickname refers to: " + nickname.name);
        System.out.println("Grade: " + nickname.grade);
        System.out.println("Pets: " + nickname.pets);
        System.out.println("Siblings: " + nickname.siblings);
    }
}

Nickname refers to: Ava Johnson
Grade: 10
Pets: 2
Siblings: 1