Question

1. Assume you have a Car class that declares two private instance variables, make and model. Write Java code that implements a two-parameter constructor that instantiates a Car object and initializes both of its instance variables. 2. Logically, the make and model attributes of each Car object should not change in the life of that object. a. Write Java code that declares constant make and model attributes that cannot be changed after they are initialized by a constructor. Configure your declarations so that get- methods are not needed to read the values of these attributes from outside the class. b. Assuming you are in a separate driver class that has already used a constructor to create and fully initialize an object called car that has constant make and model attributes, write a Java statement that prints these two attributes on one line with one space between them. 3. Assume a Car class already has a two-parameter constructor that initializes make and model attributes. Write Java code that implements an additional constructor that has three parameters ─ two String parameters to initialize the same make and model attributes initialized by the two-parameter constructor, plus another int parameter to initialize a miles variable. Your code should utilize the two-parameter constructor to implement those operations which the two-parameter constructor is already able to perform. 4. Suppose a Car class defines an equals method with this header: public boolean equals(Car car) This equals method returns true if and only if the calling object and the parameter object have the same make and model. Otherwise, it returns false.

my subject is Computer science java

Answer 1

Thanks for the question.

Here is the completed code for this problem. 

Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. 

If you are satisfied with the solution, please rate the answer. 

Thanks!
===========================================================================

public class Car {

    //1. Assume you have a Car class that declares two private
    // instance variables, make and model.

    //a. Write Java code that declares constant make and model
    // attributes that cannot be changed after
    // they are initialized by a constructor.

    // we made the variables public as they are constant
    // so once the values are set even they are public we cannot
    // directly change the values of these two attributes as they are now final
    public final String model;
    public final String make;

    // 3.plus another int parameter to initialize a miles variable.
    private int miles;

    //Write Java code that implements a two-parameter constructor
    // that instantiates a Car object and initializes both of its
    // instance variables.

    public Car(String model, String make) {
        this.model = model;
        this.make = make;
    }


    public Car(String model, String make, int miles) {
        //Your code should utilize the two-parameter constructor
        // to implement those operations which the two-parameter
        // constructor is already able to perform.
        this(model, make);
        this.miles = miles;
    }

    // class defines an equals method
    public boolean equals(Car car) {
        //This equals method returns true if and only if the calling
        // object and the parameter object have the same make and model.
        return make.equals(car.make) &&
                model.equals(car.model);
    }
}

=============================================================

public class CarDriver {

    public static void main(String[] args) {

        //initialize an object called car that has constant make and model attributes
        Car aCar = new Car("UX-123", "Ferrari");
        //prints these two attributes on one line with one space between them.
        System.out.println(aCar.make + " " + aCar.model);
    }
}

=============================================================