define another public method called howMany() which just returns how many Courses have been created. Users will ask the Course class how many have been created (see the PolymorphismMinilabDriver), so make it static. 

package polymorphismPart1;

 

//This class describes an academic course, which contains a name and a roster of Students

 

public class Course { //data private String name; private int maxCount; private int count; private Student[] roster; private static int numInstances = 0;

 

 //default constructor - sets the maxCount to 30, initializes name/count, creates array, // updates numInstances. public Course() { this.name = \"unknown\"; this.maxCount = 30; this.count = 0; this.roster = new Student[maxCount]; this.numInstances++; }

 

//************************************************ //parameterized constructor - receives name, maxCount, initializes count, creates array, // updates numInstances.

 

 //toString() - returns its representation as a String public String toString() { String outString = \"Roster of: \" + name; for (int i=0; i;> outString += \" \\t\" + (i+1) + \".\\t\" + roster[i];

 

return outString; }

 

//takeAttendance - goes through the roster, printing each Student's answer public void takeAttendance() { System.out.println(\"Taking attendance...\"); for (int i=0; i;> { Student respondant = roster[i]; System.out.println(\"\\t\" + respondant.getName() + \" (\" + respondant.getClass().getName() + \")\" + \" answers \" + respondant.answer()); } }

 

//addStudent - puts a Student into the next available roster space, updates count public void addStudent(Student newStudent) { if (count >= roster.length) System.out.println(\" \" + name + \" is full. Cannot add \" + newStudent); else roster[count++] = newStudent; //note tricky use of ++ here... } }

 

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2. add a new method called getID() to the Student class. It should just return the ID. Make sure the method is also visible to everyone.

 

package polymorphismPart1;

 

//This class describes a Student

 

public class Student { //data private String name; private int ID;

 

//default constructor public Student() { name = \"unknown\"; ID = 0; }

 

//parameterized constructor public Student(String name, int ID) { this.name = name; this.ID = ID; }

 

//toString - returns String representation of the instance public String toString() { return name + \": \" + ID; }

 

//answer - returns how the Student instance answers during attendance public String answer() { return \"\\\"Here\\\"\"; //note use of escape character here... }

 

//getName - returns the name public String getName() { return name; }

 

}

 

_______________________________________________________________________ 3. Copy your Part1CourseandStudentclass into thepolymorphismPart2package and include aparameterized Course constructor(one that can receive some arguments). This constructor should accept a String and an int and use them to set thenameand maxCount. Be sure it does the other things that the default constructor does.

 

package polymorphismPart2;

 

//This is the driver class for the program Part2

 

public class PolymorphismMinilabDriver2 { public static void main(String[] args) { //create a Student Student firstStudent = new Student(\"Joe\", 13); System.out.println(\"----- First Student is: \"); System.out.println(firstStudent);

 

//tell it to return its ID - print it. System.out.println(\" ----- Ask the first Student for its ID: \"); System.out.println(firstStudent.getID());

 

//create a new Course Course algebra = new Course(\"Algebra 1-2\", 8);

 

//tell it to add some Students algebra.addStudent(firstStudent); algebra.addStudent(new Student()); algebra.addStudent(new BrownNose(\"Peter\", 21)); algebra.addStudent(new Student(\"Janet\", 43)); algebra.addStudent(new BrownNose(\"Jim\", 243)); algebra.addStudent(new Student(\"Al\", 3)); algebra.addStudent(new BrownNose()); algebra.addStudent(new BrownNose(\"Jenn\", 23)); algebra.addStudent(new Student(\"Jose\", 43)); algebra.addStudent(new BrownNose(\"Grant\", 7));

 

//print the string representation of the course to see what is there System.out.println(\" ----- Creating a Course and telling it to add some Students. Printing it:\"); System.out.println(algebra);

 

//tell the course to take attendance System.out.println(\" ----- telling the course to take attendance\"); algebra.takeAttendance();

 

//create two more new Courses Course history = new Course(); Course spanish = new Course();

 

//ask the Course class how many have been created (static) System.out.println(\" ----- Asking the Course class how many courses have been created: \"); System.out.println(Course.howMany()); } }