Which of the following statements specify the difference between an interface and a class? O A. All methods in an interface type are abstract; they don't have an implementation O B. All methods in an interface type are automatically public O C. An interface type does not have instance fields O D. All above are correct

Which of the following statements specify the difference between an interface and a class? O A. All methods in an interface type are abstract; they don't have an implementation O B. All methods in an interface type are automatically public O C. An interface type does not have instance fields O D. All above are correct

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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3. Design a user-defined class called Course. Each course object will hold data about a course. The data includes courseID, courseName, credits and instructorName. Define the instance variables required of the appropriate type. Provide only get methods along with toString() and equals() methods. Design another user-defined class called Student. Each student object will hold data on name, GPA and courseList. Make sure to define courseList as an ArrayList holding references to Course objects Implement a constructor that will take values to initialize name, and gpa while courseList is initialized to an ArrayList() object. Provide the following get methods: getStudent ID ( ), getName(), getGPA (), get Gender(), and get CourseList() Note: the getCouresList() method will return a copy of the coureList arraylist with copies of course objects. Provide the following set methods: setName(), setGPA (), setGender() Another method: addCourse () that will take a Course object and add it to the…
Choose necessary patters, draw the UML and code just company class methods on paper. A car company makes a car produce application. There are diffrerent types of models that the company builds as sedan and sport. Each model has some shared and distinguishing features. The object creation process should conduct by a central class. The second central class should not be created in the application.
1. Create a properly encapsulated class named Person that has the following: A String instance variable called name. A constructor that takes a String parameter and sets the instance variable. A properly named getter for the instance variable. A correctly overrided equals method which returns true if the name instance variable of the parameter and the reference variable calling the method are equal. (Do not forget the null and class type checks!) Compile your Person class. 2. Create a properly encapsulated class named Employee that inherits from Person and has the following: ● ● ● A String instance variable called office (e.g. "LWH 2222"). A String instance variable called hourlywage (e.g. "$45.15"). A constructor that takes three Strings as parameters for name, office, and hourlyWage and sets the instance variables of both the parent class and the Employee class. An overridden toString method that returns the concatenation of name and hourlyWage instance variables (separated by a…
14. Which statements are true about the following code? (Choose all that apply) 1: interface HasVocalCords {2: public abstract void makeSound();3: }4: public interface CanBark extends HasVocalCords {5: public void bark();6: } A. The CanBark interface doesn’t compile.B. A class that implements HasVocalCords must override the makeSound() method.C. A class that implements CanBark inherits both the makeSound() and bark() methods.D. A class that implements CanBark only inherits the bark() method.E. An interface cannot extend another interface. Please explain this code abstract, extent and interface methods too in detail.
Which of the following statements is false? a. A class can contain only one constructor. b. An example of a behavior is the SetTime method in a Time class. c. An object created from a class is referred to as an instance of the class. d. An instance of a class is considered an object.
Using c++ programming language. Write a class Distance that holds distances or measurements expressed in feets and inches. Thisclass has two private data members: feet: An integer that holds the feet. inches: An integer that holds the inches. Write a constructor with default parameters that initializes each data member of the class.If inches are greater than equal to 12 then they must be appropriately converted tocorresponding feet. Generate appropriate getter-setter functions for the data members.o void setFeet(int f) and int getFeet()consto void setInches(int i) It should ensure proper conversion to feet.o int getInches() const Define an operator ‘+’ that overloads the standard ‘+’ math operator and allows oneDistance object to be added to another. Distance operator+ (const Distance &obj). Define an operator - function that overloads the standard ‘-‘ math operator and allowssubtracting one Distance object from another. Distance operator-(const Distance &obj)…
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Which of the given modifiers is used when an abstract method is implemented by a derived class? a. Virtual b. Base c. Override d. Static
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Overriding is useful when a method has the same signature and type as a method in the parent class. O a local variable has the same name as an instance variable. O you want to change the return type of a method. O a method has the same signature as another method in the same class.