//The function removeBook searches for the stock number
//of a Book Record and removes that book from the list.
public Boolean removeBook(long stockNum)
{
BookRecord back = new BookRecord();
BookRecord temp = new BookRecord();
BookRecord delParent = new BookRecord(); //delParent = parent of node to remove, delNode = node to remove
BookRecord delNode = new BookRecord();
String tempName = "";
temp = m_pRoot;
back = null;
if (temp == null)//Case 1: Checks to see there is anything in the tree
{
return false;
}
//Finding the node to delete.
while ((temp != null) && (stockNum != temp.getStockNum()))
{
back = temp; //makes back the parent of temp
if (stockNum < temp.getStockNum())
{
temp = temp.getLeft(); //send temp to the next node to the left
}
else
{
temp = temp.getRight(); //send temp to the next node to the right
}
}
//If tree has reached the end and no book is found, a message is printed
if (temp == null) //System didnt find anything to remove
{
Console.WriteLine("Book Not Found. Nothing was removed.\n");
return false;
}
else //Prepare for deletion
{
if (temp == m_pRoot)//If the book is at the root, set delNode to root and delParent to null
{
delNode = m_pRoot;
delParent = null;
}
else //Node to remove comes after the root node
{
delNode = temp;
delParent = back;
}
}
//Case 2: Removing node with zero or one child on the left
if (delNode.getRight() == null) //The delNode has no right child
{
if (delParent == null) //Removing the root
{
m_pRoot = delNode.getLeft(); //make the left child the new root
delNode = null;
return true;
}
else //Not at root, decide which side of delParent, delNode is on
{
if (delParent.getLeft() == delNode) //Node to delete is a left child
{
delParent.setLeft(delNode.getLeft());
}
else //Node to delete is a right child
{
delParent.setRight(delNode.getLeft());
}
delNode = null;
return true;
}
}
else //Case 3: Deleting node has at least one child on the right
{
if (delNode.getLeft() == null) //The delNode has no left child
{
if (delParent == null)//Deleting the root
{
m_pRoot = delNode.getRight(); //make the right child the new root
delNode = null;
return true;
}
else //Not at root, decide which side of delParent, delNode is on
{
if (delParent.getLeft() == delNode) //Node to remove is a left child
{
delParent.setLeft(delNode.getRight());
}
else //Node to remove is a right child
{
delParent.setRight(delNode.getRight());
}
delNode = null;
return true;
}
}
else //Case 4: Removing node with two children.
{
//Find the replacement value. Locate the node containing the largest value smaller
//than the key of the node being deleted
temp = delNode.getLeft();
back = delNode;
while (temp.getRight() != null)
{
back = temp;
temp = temp.getRight();
}
//Copy the replacement values into the
//node to be "removed"
tempName = temp.getName();
delNode.setName(tempName);
delNode.setClassification(temp.getClassification());
delNode.setCost(temp.getCost());
delNode.setNumberInStock(temp.getNumberInStock());
delNode.setStockNum(temp.getStockNum());
//delNode = temp;
//Remove the replacement node from the tree.
if (back == delNode)
{
back.setLeft(temp.getLeft());
}
else
{
back.setRight(temp.getLeft());
}
temp = null;
return true;
}
}
}
//The function searchByStockNumber searches the list for books
//with the given stock number and prints their information.
public BookRecord searchByStockNumber(long stockNum)
{
if (m_pRoot == null) //Checks if there is anything in the tree, prints message if the tree is empty
{
Console.Error.WriteLine("There are no contents in this tree!");
}
BookRecord temp = new BookRecord();
temp = m_pRoot;
//The function searches the tree until it reaches the end
while ((temp != null) && temp.getStockNum() != stockNum)
{
if (stockNum < temp.getStockNum())
{
//Search key comes before this node, send temp to left child
temp = temp.getLeft();
}
else
{
//Search key comes after this node, send temp to right child
temp = temp.getRight();
}
}
if (temp == null) //If the target is not found, return null
{
return null;
}
else //Target found!
{
temp.setLeft(null); //Safety purposes, prevents m_pLeft from being exposed to end user
temp.setRight(null); //Safety purposes, prevents m_pRight from being exposed to end user
return temp;
}
//Function won't ever get here, this is to stop the warning that "not all control paths return a value"
//return null;
}
//The addBook function adds a Book Record to the end of the list
public Boolean addBook(BookRecord br)
{
//Checks to see there is really anything on br
if (br == null)
{
return false;
}
BookRecord temp, back = new BookRecord(); //Create BookRecord instances
temp = m_pRoot;
back = null;
while (temp != null) //Loop till temp falls out of the tree
{
back = temp;
if (br.getStockNum() < temp.getStockNum())
{
temp = temp.getLeft();
}
else
{
temp = temp.getRight();
}
}
//Attach new node to the node that back points to
if (back == null) //Attach as root node in a new tree
{
m_pRoot = br;
}
else
{
if (br.getStockNum() < back.getStockNum())
{
back.setLeft(br);
}
else
{
back.setRight(br);
}
}
return true;
}