Partial Question 3 Consider: class A { } public void doA() { } class B extends A { } public void doB () { } Which of the following are allowed? B x = new B(); x.doB(); A x = new A(); x.doA(); A x = new A(); x.doB(); B x = new B(); x.doA();

Partial Question 3 Consider: class A { } public void doA() { } class B extends A { } public void doB () { } Which of the following are allowed? B x = new B(); x.doB(); A x = new A(); x.doA(); A x = new A(); x.doB(); B x = new B(); x.doA();

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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Write C++ code for a class named MuniBus that has the following private member variables: int totalPassengers; double faresCollected; and the following public member functions: void passengerBoard() - adds 2.50 to faresCollected and adds 1 to totalPassengers double getFaresCollected() - returns faresCollected int getPassengers() - returns totalPassengers void reset() - sets totalPassengers and faresCollected to zero MuniBus() - default constructor. Initializes both totalPassengers and faresCollected to 0 MuniBus(int tp, double fc) - constructor which initializes totalPassengers to tp, faresCollected to fc ~MuniBus() - destructor. Prints out a message saying that the bus is being destroyed, and also prints out totalPassengers and faresCollected. Write the class declaration and implement all of the constructors, the destructor, and member functions. You do not need to demonstrate using your class or show output.
6. Given: class Pet { public: virtual void eat() { cout eat(); } What is the result of compiling and running the above program? m. The program compiles and crashes when it runs. i. The program compiles and runs, printing "Pet::eat" j. The program compiles and runs, printing "Cat::eat" The program compiles and runs to completion without printing anything. n. o. None of the above. k. The program fails to compile because the method eat is not marked virtual in Cat. I. The program fails to compile for some other reason.
6. class PPP int H: protected : int S; public : void input (int); void out (); }; class Q0Q : private PPP int T; protected : int U; public : void indata (int, int); void outdata (); }; class RRR : public Q0Q int M; public : void disp (); }; int main () 002 objl; RRR obj2; return 0; a. In the above code, is the member function out() accessible by obj1? b. Name the member function(s), which can be accessed from the obj2? c. Name the data member(s) that can be accessed from function disp().
use the following partial class definitions:public class A1{public int x;private int y;public int z;…}public class A2 extends A1{public int a;private int b; …}public class A3 extends A2{private int q;…} 2) Which of the following lists of instance data are accessible in class A2?a) x, y, z, a, bb) x, y, z, ac) x, z, a, bd) z, a, be) a, b
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Consider the following class: class Complex { double x, y; public: Complex(double newX, double newY) { x = newX; y = newY; Complex operator+(const Complex& c) { Complex temp; temp.x = this->x + c.x; temp.y = this->y + C.y; return temp; } friend ostream& operator<< (ostream& out, const Complex& c) { out << c.x << " + " << c.y << '"i"; return out; } }; Let the following objects be defined: Complex a(1, 2); Complex b(3, 4); Complex c = a + b; What is the output of the statements below?
Problem 4) Suppose the following Course class is given: public class Course { private String name;//such as CS, MATH, etc private int grades[];//list of the grades //default and initial valued constructor //all other methods public double average() { double sum=0; for(int i=0;i=90) System.out.printf("me is a student with A letter-grade\n");
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Instructions-Java Assignment is to define a class named Address. The Address class will have three private instance variables: an int named street_number a String named street_name and a String named state. Write three constructors for the Address class: an empty constructor (no input parameters) that initializes the three instance variables with default values of your choice, a constructor that takes the street values as input but defaults the state to "Arizona", and a constructor that takes all three pieces of information as input Next create a driver class named Main.java. Put public static void main here and test out your class by creating three instances of Address, one using each of the constructors. You can choose the particular address values that are used. I recommend you make them up and do not use actual addresses. Run your code to make sure it works. Next add the following public methods to the Address class and test them from main as you go: Write getters and…
Code: import java.util.*; //Bicycle interface interface Bicycle { abstract void changeCadence(int newValue); //will change value of candence to new value abstract void changeGear (int newValue); //changes gear of car abstract void speedUp(int increment); //increments speed of car by adding new Value to existing speed abstract void applyBrakes(int decrement); } //ACMEBicycle class definition class ACMEBicycle implements Bicycle { int cadence = 0; Â Â int speed = 0; Â Â int gear = 1; //methods of interface public void changeCadence(int newValue) { this.cadence=newValue; } public void changeGear (int newValue) { this.gear=newValue; } public void speedUp(int increment) { this.speed+=increment; } public void applyBrakes(int decrement) { this.speed-=decrement; } //display method void display() { System.out.println("Cadence: "+this.cadence); System.out.println("Gear: "+this.gear); System.out.println("Speed: "+this.speed); } } //KEYOBicycle class definition class KEYOBicycle implements…
public class Cat extends Pet { private String breed; public void setBreed(String userBreed) { breed = userBreed; } public String getBreed() { return breed; }} public class Pet { protected String name; protected int age; public void setName(String userName) { name = userName; } public String getName() { return name; } public void setAge(int userAge) { age = userAge; } public int getAge() { return age; } public void printInfo() { System.out.println("Pet Information: "); System.out.println(" Name: " + name); System.out.println(" Age: " + age); } } import java.util.Scanner; public class PetInformation { public static void main(String[] args) { Scanner scnr = new Scanner(System.in); // create a generic Pet and a Cat Pet myPet = new Pet(); Cat myCat = new Cat(); // declare variables for pet and cat info String petName, catName, catBreed; int petAge,…
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