Thread: Help with increasing size of an array

Hello all,

I'm working on an assignment that says the following.

"

1. The array size is fixed in Listing 10.6. Improve it to automatically increase the array size by creating a new larger array and copying the contents of the current array to it.
2. Implement the dropStudent method.
3. Add a new method named clear() that removes all students from the course.

Write a test program that creates a course, adds three students, removes one, and displays the students in the course."

10.6 Listing

public class Course {
 
	private String courseName;
	private String[] students = new String[100];
	private int numberOfStudents;
 
	}
 
		public Course(String courseName) {
		this.courseName= courseName;
	}
 
	public void addStudent(String student) {
		students[numberOfStudents] = student;
		numberOfStudents++;
	}
 
	public String[] getStudents() {
		return students;
	}	
 
	public int getNumberOfStudents() {
		return numberOfStudents;
	}	
 
	public String getCourseName(){
		return courseName;
	}
 
	public void dropStudent(String student) {
		//Left as exercise;
	}
 
 
	}
 
 
 
}

My Test Code based off of book

public static void main(String[] args) {
		Course course1= new Course("Business");
 
 
		course1.addStudent("Jay");
		course1.addStudent("Silent Bob");
		course1.addStudent("Dante");
 
		course1.dropStudent("Jay");
 
		System.out.println("Number of students in course1: " +course1.getNumberOfStudents());
		String[] students= course1.getStudents();
		for (int i=0; i< course1.getNumberOfStudents(); i++)
			System.out.println(students[i] + " , ");}
 
 
	}

My adjusted 10.6

public class Course {
 
	private String courseName;
	private String[] students = new String[100];
	private int numberOfStudents;
 
	}
 
		public Course(String courseName) {
		this.courseName= courseName;
	}
 
	public void addStudent(String student) {
		students[numberOfStudents] = student;
		numberOfStudents++;
	}
 
	public String[] getStudents() {
		return students;
	}	
 
	public int getNumberOfStudents() {
		return numberOfStudents;
	}	
 
	public String getCourseName(){
		return courseName;
	}
 
	public void dropStudent(String student) {
		students[numberOfStudents] = student;
		numberOfStudents--;
	}
 
	public void Clear(){
		student.length= 0;
	}
 
 
 
}

The problem I'm having is, for the first part of the question where I need to automatically increase the array size. I'm really not great at this stuff. I have tried breaking it down, but can't "get it", I guess.

I assume, it'd be a loop that checks to see if the student array is full and if so, do the increaseArray() part, by maybe multiplying the student array and then assigning it. I just don't know how to do it haha. Any advice or breadcrumbs would be appreciated.

My *best* attempt at the loop so far has been

if (students == students.length){
int bigArray = 2*students.length;
String increaseArray()= new String[students];
System.arraycopy(students, 0, increaseArray, 0, students.length);
students= increaseArray;

but,yeah... Doesn't seem to be right.

Welcome to the forum! Thanks for taking the time to learn to post code correctly.

Please give your threads better titles. I'll change this one for you.

Why/how is the general algorithm for increasing the size of the array that you posted not working? Show the code for just that part, if it exists.

Oh, sorry about that. I'm bad at titles. Meant to go back and redo, but forgot!

This is the part. After this section, it's just like the one above.

public class Course {
 
	private String courseName;
	private String[] students = new String[100];
	private int numberOfStudents;
 
	}
 
	if (students == students.length){
		bigArray= 2*students.length;
		String increaseArray()= new String[students];
		System.arraycopy(students, 0, increaseArray, 0, students.length);
		students= increaseArray;
	}

*edit* Prematurely posted!
Maybe the placement is wrong or maybe I'm doing method wrong to use for the TestCourse or not really understanding the call aspect. To make sure, once I make the methods and such, do I then copy and use it on the TestCourse? If not, that would explain a lot of my confusion. It's been a couple years since my last Java class, so I'm still remembering stuff.

I get the errors at if, int bigArray, and String IncreaseArray.

if- invalid AnnotationName
Int bigArray- says to put a }, but then when I do, more and more errors show up.
Increase- same as above

Show the code. We're not omniscient.