Help!!!

[K.O.I]

Hi i am a new to java and having a little trouble can anybody tell me what is wrong with this code, only Person compiles and runs, any help will be greatly appreciated.


class Student extends Person
{

// instance variables

protected String course;
protected int year;


// constructors

public Student(String nme, char sex, Date dob, String insceNumber,String S, int yr)
{

super(nme,sex,dob,insceNumber);
course=S;
year=yr;


}


public Student ()
{

course="Unknown";
year=0;
}

// transformers

public void setYear(int yr)
{
year=yr;
}

public void setCourse(String S)
{
course=S;
}

public void copy(Student other)
{
super.copy(other);
course=other.course;
year=other.year;

}

//accessors



public boolean sameAs(Student other)
{
return super.equals(other) && year==other.year && course==other.course;
}

public String toString()
{
return (super.toString()+"Year:"+year+"Course:"+course);
}
}

public class Person
{
// instance variables

protected String name;
protected String gender;
protected Date dateofBirth;
protected String address;
protected String natInsceNo;


// class variable

private static int counter;

//class methods

public static int count()
{
return counter;
}

//constructors

public Person(String nme, char sex, Date dob,String insceNumber, String add)
{
name=nme;
//setGender(sex);
dateofBirth=dob;
natInsceNo=insceNumber;
address=add;
counter++;
}

//transformers

public void setGender (char sex)
{
if (sex=='m' || sex=='M')
gender="Male";
else if (sex=='f' || sex=='F')
gender = "Female";
else gender="Unknown";
}

public void setdateofBirth(Date dob)
{
dateofBirth=dob;
}

public void setName (String nme)
{
name=nme;
}

public void setnatInsceNo (String insceNumber)
{
natInsceNo=insceNumber;
}

public void setaddress (String add)
{
address=add;
}

public void copy(Person other)
{
name=other.name;
gender=other.gender;
dateofBirth=other.dateofBirth;
address=other.address;
natInsceNo=other.natInsceNo;
}


//accessors

public String toString()
{
return "\n"+"Name: "+name+"\n"+"Date Of Birth: "+dateofBirth+"Gender: "+gender+"\n"+"Address : "+address+"\n"+"National Insurance No: "+natInsceNo+"\n";
}

public boolean equals(Person other)
{
if(name == other.name && natInsceNo==other.natInsceNo)
{
return true;
}
else
{
return false;
}
}
public Person()
{
name="unknown";
address="unknown";
natInsceNo="unknown";
counter++;
}

public String getName()
{
return name;
}

public String getGender()
{
return gender;
}

public String getAddress()
{
return address;
}

public String getNatInsceNo()
{
return natInsceNo;
}

public Date dateofBirth()
{
return dateofBirth;
}
}


class Store
{
private Person[] list;
private int count;
private int maxSize;

//constructor

Store(int max)
{
maxSize = max;
list= new Person[maxSize];
count=0;
}

//transformer

public void add(Person p)
{
if(count != maxSize)
{
list [count] = p;
System.out.println("Person "+p.name+" stored at "+count+" in store");
count++;
}
else
{
System.out.println("Person "+p.name+" Store Full");
}
}

//accessors

public boolean isFull()

{
if (count == maxSize)
{
return true;
}
else
{
return false;
}
}

public int getCount()
{
return count;
}

public void displayAll()
{
int nCount=0;
while (nCount < count)
{

System.out.println("Location:"+nCount+"\n"+"Contains:"+"\n"+list[nCount].toString()+"\n");
nCount++;
}
}
}

[sjalle]

Its this statement in the Student constructor:

super(nme,sex,dob,insceNumber);

the statement invokes the Person constructor, and that signature is like:

public Person(String nme, char sex, Date dob, String insceNumber, String add)

You have forgotten the address parameter, and, I think you need to import something
to support your Date object, like:

import java.sql.Date;

You should also write the equals method in Person like:

public boolean equals(Object ob) {
    if (!(ob instanceof Person)) return false;
    Person other=(Person)ob;
    if (name == other.name && natInsceNo == other.natInsceNo) {
      return true;
    }
    else {
      return false;
    }
}

... and change the sameAs method in Student to

  public boolean equals(Object ob) {
    if (!(ob instanceof Student)) return false;
    Student other=(Student)ob;
    return super.equals(other) && year == other.year && course == other.course;
  }

The reason is that the
public boolean equals (Object element)
method is vital in many of the collection classes utilization.

I have tried to explain it in this example:

import java.util.*;
class Student {
  private int id=-1;
  private String name="";
  public Student (int id, String name) {
    this.id=id;
    this.name=name;
  }
  public Student (String name) {
    this.name=name;
  }
  public String getName() {  return name; }
  public int getID () { return id; }

  public String toString() {
    return "Student: ID: "+id+", name: "+name;
  }
  public boolean equals(Object ob) {
    if (!(ob instanceof Student)) return false;
    Student aStudent=(Student)ob;
    return name.trim().equals(aStudent.getName().trim());
  }
}
public class VectorExample {
  Vector v=null;
  public VectorExample() {
    v=new Vector();
  }
  public void test() {
    v.addElement(new Student(1,"John"));
    v.addElement(new Student(2,"Mary"));
    v.addElement(new Student(3,"Peter"));

    System.out.println("Vector contains "+v.size()+" objects");

    //lookup-find by object
    if (!find ("Mary")) System.out.println("Student: Mary not found");
    if (!find ("Peter")) System.out.println("Student: Peter not found");
    if (!find ("John")) System.out.println("Student: John not found");
    if (!find ("Butthead")) System.out.println("Student: Butthead not found");
    v.remove(new Student("Mary"));
    System.out.println("Vector contains "+v.size()+" objects");
    if (!find ("Mary")) System.out.println("Student: Mary not found");
    int ix=v.indexOf(new VectorExample());
    System.out.println(ix);
  }
  public boolean find(String name) {
    int ix=v.indexOf(new Student(name));
    if (ix >= 0) {
      System.out.println("Index: " + ix + " contains: " + v.elementAt(ix));
      return true;
    }
    else
      return false;
  }
  public static void main(String[] args) {
    VectorExample ve = new VectorExample();
    ve.test();
  }
}

PS: please use the code tag around big blocks of code, I think it will increase your
chances of getting responses...

[K.O.I]

Thanks for your help!!