draw the state-of-memory diagram at the point immediately after the last statement is executed

1.Given the Fraction class from Section 7.8, draw the state-of-memory diagram at the point immediately after the last statement is executed.

Fraction f1, f2, f3;

f1 = new Fraction(3, 8);

f2 = new Fraction(2, 3);

f3 = f1.add(f2);

2.Consider the following class.

class Dog {

. . .

private double weight;

. . .

public boolean isBiggerThan(Dog buddy){

return this.getWeight() > buddy.getWeight();

}

public double getWeight() {

return weight;

}

. . .

}

For each of the following code fragments, complete the state-of-memory diagram by filling in the arrows for this and buddy.

Dog tuffy = new Dog(…);

Dog puffy = new Dog(…);

puffy.isBiggerThan(tuffy);

Dog tuffy = new Dog(…);

Dog puffy = new Dog(…);

tuffy.isBiggerThan(puffy);

Complete the following constructor.

class Student { private String

name;

private int

age;

private Address address;

public Student(String name, int age, Address address){

//assign passed values to the data members

The Correct Answer and Explanation is :

Let’s go step by step to address your questions.

1. State-of-Memory Diagram for Fraction Class

In the provided code:

Fraction f1, f2, f3;
f1 = new Fraction(3, 8);
f2 = new Fraction(2, 3);
f3 = f1.add(f2);

• f1 and f2 are reference variables of type Fraction.
• f1 = new Fraction(3, 8) creates an object of Fraction with numerator 3 and denominator 8, and assigns the reference to f1.
• f2 = new Fraction(2, 3) creates an object of Fraction with numerator 2 and denominator 3, and assigns the reference to f2.
• f3 = f1.add(f2) calls the add method on f1, passing f2 as a parameter. The method performs addition of the fractions and creates a new Fraction object, which is assigned to f3.

State-of-Memory Diagram:

• f1 points to a Fraction object with numerator = 3 and denominator = 8.
• f2 points to a Fraction object with numerator = 2 and denominator = 3.
• f3 points to a new Fraction object, the result of f1.add(f2). The exact result would depend on how the addition is implemented, but typically this would result in a fraction like (3/8 + 2/3) which can be simplified.

2. Dog Class Memory Diagrams

For the Dog class, you’re working with two dogs, tuffy and puffy. Let’s break down the scenarios.

First case: puffy.isBiggerThan(tuffy);

In this case, puffy calls isBiggerThan on tuffy. So:

• this refers to puffy.
• buddy refers to tuffy.

The method compares the weight of puffy to tuffy and returns whether puffy is bigger.

Second case: tuffy.isBiggerThan(puffy);

Here, tuffy calls isBiggerThan on puffy. So:

• this refers to tuffy.
• buddy refers to puffy.

The method compares the weight of tuffy to puffy and returns whether tuffy is bigger.

3. Constructor for Student Class

You need to write the constructor for the Student class:

class Student {
    private String name;
    private int age;
    private Address address;

    public Student(String name, int age, Address address) {
        this.name = name;        // Assign the passed name to the instance variable
        this.age = age;          // Assign the passed age to the instance variable
        this.address = address;  // Assign the passed address to the instance variable
    }
}

This constructor takes three parameters: name, age, and address, and assigns them to the instance variables name, age, and address of the Student object being created.

Explanation:

1. Constructor Definition: The constructor Student(String name, int age, Address address) is called whenever a new Student object is instantiated. It initializes the fields name, age, and address with the values provided during object creation.
2. this Keyword: The this keyword refers to the current instance of the class. In the constructor, it is used to differentiate the instance variables (e.g., this.name) from the parameters (e.g., name), especially when the parameter names are the same as the instance variable names.
3. Data Members Initialization: The constructor assigns the provided values to the corresponding fields:

• this.name = name: Assigns the value of the name parameter to the name field.
• this.age = age: Assigns the value of the age parameter to the age field.
• this.address = address: Assigns the value of the address parameter to the address field.

This ensures that when a Student object is created, its attributes are properly initialized.