Link List of Integers

[onip28]

Hello,

First off, I'm new to programming so if you're reading my post and shaking heads, please bear with me . I'm currently doing some practice programs for my Java class dealing with Linked Structures.

I have a IntList.java class which contain the definitions for a linked list of integers. The class also contains an inner class IntNode, which holds info for a single node within the list and the following IntList methods of:

public IntList()
public void addToFront(int val)
public void addToEnd(int val)
public void removeFirst()
public void print()

I then have an IntListTest.java file that let's me use these methods...Here's where things get complicated (for me anyways); I'm suppose to add the following methods into the IntList clas, and add the option to the driver IntListTest...

public int length() -- which returns the number of elements in the list
public String toString() -- returns a String containing the print val of the list
public void removeLast()
public void search(int input)
public void insertAt(int index, int newValue)
public void removeAt(int index)

The only thing that I need is advice on how to start adding each method. This class would be a lot easier if it were face to face, but this is an online course that is proving to be certainly challenging. I hope anyone can provide input for this program. F.Y.I: I using a java compiler version 1.5...

Onip28

[evlich]

So you should have an IntList.java file that looks something like:

public class IntList {
  public IntList() { ... }
  public void addToFront(int val) { ... }
  public void addToEnd(int val) { ... }
  public void removeFirst() { ... }
  public void print() { ... }
}

In order to add a method to the class, you just need to add another method declaration. e.g.

public class IntList {
  public IntList() { ... }
  public void addToFront(int val) { ... }
  public void addToEnd(int val) { ... }
  public void removeFirst() { ... }
  public void print() { ... }

  public int length() { ... }
  public String toString() { ... }
  public void removeLast() { ... }
  public void search(int input) { ... }
  public void insertAt(int index, int newValue) { ... }
  public void removeAt(int index) { ... }
}

I put "..." where the actual code for each method gets filled in. I'm not sure exactly what your IntListTest.java looks like. I would guess that it is a JUnit test class in which case it would look something like:

public class IntListTest extends TestCase {
  public void testAddToFront() { ... }
  public void testAddToEnd() { ... }
  public void testRemoveFirst() { ... }
  public void testPrint() { ... }

  public int testLength() { ... }
  public String testToString() { ... }
  public void testRemoveLast() { ... }
  public void testSearch() { ... }
  public void testInsertAt() { ... }
  public void testRemoveAt() { ... }
}

In this case you would fill in the "..." with code to test your functions and assert statements. For example a very simple test for the length() function might be:

public void testLength() {
  IntList list = new IntList();
  assertEquals("list should start as empty", list.length(), 0);
  
  list.addToFront(2);
  assertEquals("list with 1 element should have length of 1", list.length(), 1);

  list.addToFront(1);
  assertEquals("list with 2 elements should have length of 2", list.length(), 2);
}

This probably wouldn't be enough to throughly test the length() method but it's a start.

Hope this helps.