1. COMPUTER 2430 Object Oriented Programming and Data Structures I

2. Container Classes Class IntegersList of Lab1 Class ScoresList of Prog1
Class GolfLeague of Prog2
How to store multiple values?
Arrays
Linked Lists (CS 2630 – OOPS II)

3. Container Methods Adding elements Deleting elements Searching targets
Updating elements
Displaying elements
. . .

4. public class StudentList{
private final int MAX_SIZE = 450;
private Student[] studentList = new Student[MAX_SIZE];
private int numStudents = 0;
public boolean addStudent( Student student )
. . .
public boolean removeStudent( Student student )
private int find ( Student student )
@Override
public String toString () }

5. public class StudentList{
private final int MAX_SIZE = 450;
private Student[] studentList = new Student[MAX_SIZE];
private int numStudents = 0;
public boolean addStudent( Student student )
if (num < MAX_SIZE)
studentList[numStudents ++] = student;
return true; }
return false;
. . .

6. What if we want to store more than 450 students?
public class StudentList {
private final int MAX_SIZE = 450;
private Student[] studentList = new Student[MAX_SIZE];
private int numStudents = 0;
public boolean addStudent( Student student )
if (num < MAX_SIZE)
studentList[numStudents ++] = student;
return true; }
return false;
. . .

7. How to Grow an Array?
Make a New Larger Array!

8. public class StudentList{
private final int MAX_SIZE = 450;
private Student[] studentList = new Student[MAX_SIZE];
private int numStudents = 0;
public void addStudent( Student student )
if (numStudents == MAX_SIZE)
grow();
studentList[numStudents ++] = student; }
private void grow()
. . .

9. public class StudentList{
private final int MAX_SIZE = 450;
private Student[] studentList = new Student[MAX_SIZE];
private int numStudents = 0;
private final int GROWBY = 50;
private void grow ()
// Make a larger array
int size = MAX_SIZE + GROWBY;
Student[] list = new Student[size];
// Copy all existing elements
for (int i = 0; i < numStudents; i ++)
list[i] = studentList[i];
// Point to the new array, since studentList is
// the class field and all methods use it.
studentList = list; }

10. Only works the first time!
Correct?
public void addStudent( Student student ) {
if (numStudents == MAX_SIZE)
grow();
studentList[numStudents ++] = student; }
Only works the first time!

11. Correct! public void addStudent( Student student ) {
// if (numStudents == MAX_SIZE)
if (numStudents == studentList.length)
grow();
studentList[numStudents ++] = student; }

12. Correct? private void grow () { int size = MAX_SIZE + GROWBY;
Student[] list = new Student[size];
for (int i = 0; i < numStudents; i ++)
list[i] = studentList[i];
studentList = list; }

13. Correct! private void grow () {
int size = studentList.length + GROWBY;
Student[] list = new Student[size];
for (int i = 0; i < numStudents; i ++)
list[i] = studentList[i];
studentList = list; }

14. Method arraycopy private void grow () {
int size = studentList.length + GROWBY;
Student[] list = new Student[size];
for (int i = 0; i < numStudents; i ++)
list[i] = studentList[i];
// System.arraycopy(studentList, 0,
// list, 0, numStudents);
// DO NOT USE arraycopy!
studentList = list; }

15. Prog2

16. /**
Uses a scanner to get input from a file and from
System.in if the file unavailable.
It reads in one command at a time until end of input. */
public static void main(String [] args) {
try
sc = new Scanner( new File("Prog2_1.in") ); }
catch (Exception ex)
sc = new Scanner( System.in );
. . .

17. public static void main(String [] args){
try
. . .
String command;
while ( sc.hasNext() )
command = sc.next().toLowerCase();
switch (command)
case "add":
addMember();
break; }

18. Quiz 2
10 points
25 minutes