Question

Implement a superclass Person. Make two classes, Student and Instructor, that inherit from Person. A person has a name and a year of birth. A student has a major, and an instructor has a salary. Writhe the class definitions, the constructors, and the methods toString for all classes. For Person the constructors should include a no-arg constructor and one that accepts in the name of the person. For student there should be a no-arg constructor and a constructor that accepts in both name and major. And, for Instructor there should be a no-arg constructor as well as one that accepts in name and salary.

Supply a test program that exercises all of the capabilities of each class.

Answer 1

public class Person {
   public String name;
   public int year;
   // no-arg constructor
   Person(){
       name = "DEFAULT";
       year = 0;
   }
   Person(String name){
       this.name = name;
       year = 0;
   }
   public String toString(){
       return String.format("Name: %s\nYear: %d", name, year);
   }
  
}

_______________________________________________________________________________________

$\underline{Student.java}$

public class Student extends Person{
   private String major;
   Student(){
       super();
       major = "DEFAULT";
   }
   Student(String name, String major){
       super(name);
       this.major = major;
   }
   public String toString(){
       return super.toString() + String.format("\nMajor: %s", major);
   }
}

__________________________________________________________________________________________

$\underline{Instructor.java}$

public class Instructor extends Person{
   private double salary;
   Instructor(){
       super();
       salary = 0;
   }
   Instructor(String name, double salary){
       super(name);
       this.salary = salary;
   }
   public String toString(){
       return super.toString() + String.format("\nSalary: %.2f", salary);
   }
}

__________________________________________________________________________________________

$\underline{PersonTest.java}$

public class PersonTest {
   public static void main(String args[]){
       Student s1 = new Student();
       Student s2 = new Student("Student2", "Major2");
       Instructor i1 = new Instructor();
       Instructor i2 = new Instructor("Instructor2", 20);
       Person p1 = new Person();
       Person p2 = new Person("Person2");
       System.out.println("Student 1: \n" + s1);
       System.out.println("\nStudent 2: \n" + s2);
       System.out.println("\nInstrucotr 1: \n" + i1);
       System.out.println("\nInstrucotr 2: \n" + i2);
       System.out.println("\nPerson 1: \n" + p1);
       System.out.println("\nPerson 2: \n" + p2);
   }
}

_____________________________________________________________________________________________

$\underline{Output:}$

Answer 2

class Person {
  private String name;
  private int year;
  Person(String name, int year) {
    this.name = name;
    if (year <= 2012) this.year = year;
    else this.year = -1;
  }
  public String toString() {
    return "My name is "+ this.name + this.year + "This is a string";
  }
}

class Student extends Person {
  String major;
  Student(String name, int year, String major) {
    super(name, year);
    this.major = major;
  }
  public String toString() {
    return "" + super.toString() + this.major;
  }
}

class Instructor extends Person {
  double salary;
  Instructor(String name, int year, double salary) {
    super(name, year);
    this.salary = salary;
  }
  public String toString() {
    return "Instructor: " + super.toString() + " with salary " + this.salary;
  }
}

class Story {
  public static void main(String[] args) {
    Instructor a = new Instructor("Laura", 1980, 12345.67);
    Student b = new Student("Janice", 1965, "History");
    Person c = new Instructor("Bob", 1979, 10000.01);
    Person d = new Student("Joe", 1995, "Accounting");
    Person e = new Person("Johnny Bravo", 1991);
    System.out.println( a );
    System.out.println( b );
    System.out.println( c );
    System.out.println( d );
    System.out.println( e );


  }
}