0

Ok, the code is almost done and I need help finishing up my delete function(between lines 51 to 71), I can't seem to figure out how to delete the 50 and the 20. Here is my code. BTW i'll list the output first. Thanks
Sample output
10 20 30 50 60 80
10 20 30 50 60 80
Tree after deleting 20:
10 30 50 60 80
Tree after deleting 50:
10 30 60 80
Tree is not empty.

public class BinarySearchTree
{

	private class node
	{
		int data;
		node leftchild;
	     node rightchild;
	}
 
   	public BinarySearchTree()
	{ //create an empty Binary Search Tree }
//node root = new node;
root=null;
	
	}
	
	
   	public boolean empty()
{ // return true if the tree is empty, otherwise return false }
 if ( root == null ){
 return true;
 }else{
 return false;
 }

}
   	public void Insert(int x)
{//insert a value x }
  //search for a location to insert
  node p=root; 
  node q=null;
  while(p!=null){
   q=p;
   if(x == p.data){ return;
 }  
	if(x < p.data){ p=p.leftchild;
   }else{ p=p.rightchild;
 }
}
// create the new node
  p=new node();
  p.data = x;
  p.leftchild = p.rightchild = null;
//attaching the new node to the tree
  if(root==null){ root = p;
  }else if(x < q.data){ q.leftchild=p;
  }else{ q.rightchild = p;
  }
  return;
  }
public void Delete(int x)
{//if value x is in the tree, remove x }

//make node for q and p
node q = new node();
node p = new node();
q=p=root;

while(q==null)
{
if(x==p.data)
break;
q=p;
if(x < p.data)
p = q.leftchild;
else
p=p.rightchild;
}
if(p!=null){
p=p.rightchild;
}
}

public void Display()
{// Display the data values from smallest to largest }
 Display (root); 
}
public void Display(node p) 
{ 
	if(p!= null){ 
		Display(p.leftchild); 
		System.out.println(p.data); 
		Display(p.rightchild); 
	} 
}


   	private node root;//pointer to the root node 
}

----------------MAIN------------------------------------------------ 

public class BinarySeachtreeMain{
public static void main(String[] arg)
{
    BinarySearchTree X = new BinarySearchTree();
    
X.Insert(50);
    	X.Insert(10);
    	X.Insert(20);
	X.Insert(80);
	X.Insert(60);
	X.Insert(30);

     	X.Display();


     

     X.Delete (20);
     System.out.println ("Tree after deleting 20:");
     X.Display();
     X.Delete(50);
     System.out.println ("Tree after deleting 50:");
     X.Display();

     if(!X.empty())
	System.out.println("Tree is not empty.");
}     
}
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Last Post by BestJewSinceJC
0

http://www.csee.umbc.edu/courses/undergraduate/341/fall08/Lectures/Trees/BST.pdf

Read those lecture notes. They literally have the remove method in them. So assuming the rest of your code is correct, look at the remove method in those notes and compared it to your delete method. Once you figure out whats different, try to figure out why your code is wrong. If you can't, point out the sections of your code where its different from the correct remove() method and ask us for some help from there. Good luck

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