Question

A Java Program

Purpose:         Work with Abstract classes.

Purpose:         Abstract classes are import because they ensure than any children which inherit from it must implement certain methods. This is done to enforce consistency across many different classes.

Problem:        Implement a class called Student. This class needs to be abstract and should contain a String for the name, and a String for the major (and they should be private). The class must have a constructor to set the name and major. The class needs the following public methods: getName() and getMajor() that are used to return the associated data. It also needs two public abstract methods: setClassification(String) takes a string that will be used to set classification and should return nothing. getClassification() that will return a string containing the classification.

                       

Implement a class call UnderGraduate that inherits Student. This class must contain a private String for storing classification. It must have a constructor that takes 3 strings: name, major, and classification. This constructor must pass the name and major to the parent constructor and set the classification in its own member variable.

                       

Implement a class called Graduate that inherits from Student. This should look the same as the UnderGraduate class as far as the constructor and member variable.

For an UnderGraduate, the classification will be “Freshman”, “Sophomore”, “Junior”, and “Senior”. For a Graduate the classification will be “Masters” or “Doctoral”. Be careful we used consistent spelling (for now).

Input:             Write a test class, HW7, that creates at least 2 Undergrad objects and 2 Grad objects and populate them with information and different classifications. Have this class test out all of the functionality.

Output:           Output the required information as indicated in the problem in the "Input" section above.

Answer 1

Code:

abstract class Student  //abstract class Student
{
    private String name, major; //all data members are private
    Student(String name, String major)  //parametrized constructor
    {
        this.name = name;
        this.major = major;
    }
    public String getName() //getter method for name
    {
        return name;
    }
    public String getMajor()    //getter method for major
    {
        return major;
    }
    public abstract void setClassification(String classfication);   //abstract method which has to be overriden by child class
    public abstract String getClassification(); //abstract method which has to be overriden by child class
}
class UnderGraduate extends Student //UnderGraduate class extending from Student class
{
    private String classification;
    UnderGraduate(String name, String major, String classification) //Parametrized constructor
    {
        super(name, major); //base class constructor call
        this.classification = classification;   
    }
    public void setClassification(String classification)   //overriden setter method for classification
    {
        this.classification = classification;
    }
    public String getClassification()   //overriden getter method for classification
    {
        return classification;
    }
}
class Graduate extends Student  //Graduate class extending from Student class
{
    private String classification;
    Graduate(String name, String major, String classification)  //Parametrized constructor
    {
        super(name, major); //base class constructor call
        this.classification = classification;
    }
    public void setClassification(String classification)    //overriden setter method for classification
    {
        this.classification = classification;
    }
    public String getClassification()   //overriden getter method for classification
    {
        return classification;
    }
}
public class HW7{   //HW7 the tester class
     public static void main(String []args){    //main method
        UnderGraduate ug1 = new UnderGraduate("UG Name 1", "UG Major 1", "Freshman");   //defined 2 undergraduates
        UnderGraduate ug2 = new UnderGraduate("UG Name 2", "UG Major 2", "Senior");
        System.out.println("Name: "+ug1.getName()+" Major: "+ug1.getMajor()+" Classification: "+ug1.getClassification());
        ug2.setClassification("Junior");
        System.out.println("Name: "+ug2.getName()+" Major: "+ug2.getMajor()+" Classification: "+ug2.getClassification());
        Graduate g1 = new Graduate("G Name 1", "G Major 1", "Masters"); //definied 2 graduates
        Graduate g2 = new Graduate("G Name 1", "G Major 2", "Doctoral");
        System.out.println("Name: "+g1.getName()+" Major: "+g1.getMajor()+" Classification: "+g1.getClassification());
        g2.setClassification("Masters");
        System.out.println("Name: "+g2.getName()+" Major: "+g2.getMajor()+" Classification: "+g2.getClassification());
     }
}

Code Screenshots:

{ ہا { } 36 } 37 class Graduate extends Student //Graduate class extending from Student class 38 { 39 private String classification; 40 Graduate(String name, String major, String classification) //Parametrized constructor 41. 42 super(name, major); //base class constructor call 43 this.classification classification; 44 45 public void setClassification(String classification) //overriden setter method for classification 46 47 this.classification = classification; 48 49 public String getClassification() //overriden getter method for classification 50 51 return classification; 52 53 } 54 - public class HW7{ //HW7 the tester class 55 public static void main(String []args) { //main method 56 UnderGraduate ug1 = new UnderGraduate("UG Name 1", "UG Major 1", "Freshman"); //defined 2 undergraduates 57 UnderGraduate ug2 = new UnderGraduate("UG Name 2", "UG Major 2", "Senior"); 58 System.out.println("Name: "+ug1.getName()+" Major: "+ug1.getMajor()+" classification: "+ug1.getClassification()); 59 ug2.setClassification("Junior"); 60 System.out.println("Name: "+ug2.getName()+" Major: "+ug2.getMajor()+" classification: "+ug2.getClassification()); 61 Graduate g1 = new Graduate("G Name 1". "G Major 1", "Masters"); //definied 2 graduates 62 Graduate g2 = new Graduate("G Name 1", "G Major 2", "Doctoral"); 63 System.out.println("Name: "+g1.getName()+" Major: "+g1.getMajor()+" Classification: "+g1.getClassification()); 64 g2.setClassification("Masters"); 65 System.out.println("Name: "+g2.getName()+" Major: "+g2.getMajor()+" Classification: "+g2.getClassification()); 66 } 67 } 68 { }

Output:

Name: UG Name 1 Major: UG Major 1 Classification: Freshman Name: UG Name 2 Major: UG Major 2 Classification: Junior Name: G Name 1 Major: G Major 1 Classification: Masters Name: G Name 1 Major: G Major 2 Classification: Masters

Each and everything is explained in the comment section of the code.

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