HELP!! Binary trees

I have to write code for a collection of values using a binary tree, one of the methods is a belongs method to see if the value the user inputs is in the collection. It returns true if the value is in the collection and false if its not. I wrote a main method to test it but every time I run it I get false even if the values in the collection. To me the code I wrote seems like it should work, but obviously that is not the case, so I decided to post it here to see if I could get some help on this. I also need help on a print method for printing the values in the binary tree, but Ill just take it one method at a time for now :D

Thanks

Code:

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public class Intcoll6
{
          private btNode c;
          private int how_many;

          public Intcoll6()//default constructor
          {
                  c = null;
              how_many = 0;
          }

          public Intcoll6(int i)// alt constructor
          {
                  c = null;
              how_many = 0;
          }

          public boolean belongs(int i)// This is where I am having trouble should return true if the values in the binary tree
          {
                  btNode p = c;
                  while((p != null) && (p.info != i))
                  {
                          if(i < p.info)                         
                          {
                                  p = p.lt;
                          }
                          else
                          {
                                  p = p.rt;
                          }
                  }
                  return (p != null);
          }

          public void insert(int i)// inserts a value into the binary tree
          {
                  btNode p = c, q = null;
                  while((p != null) && (p.info != i))
                  {
                          q = p;
                          if(i < p.info)
                          {
                                  p = p.lt;
                          }
                          else
                          {
                                  p = p.rt;
                          }
                         
                  }
                 
                  if(p == null)
                  {
                          how_many++;
                          p = new btNode();
                          p.info = i;
                         
                          if(q != null)
                          {
                                  if(i < q.info)
                                  {
                                          q.lt = p;
                                  }
                                  else
                                  {
                                          q.rt = p;
                                  }
                          }
                  }
                  else
                  {
                          c = p;
                  }
                       
          }

          public int get_howmany()//counts the amount of values in the collection
          {
              return how_many;
          }

          public void print(btNode p)//prints out the collection, not sure how to do this yet, any help would be appreciated :)
          {
                       
          }
         
         
          private class btNode
          {
                  private int info;
                  private btNode lt;
                  private btNode rt;
                 
                  public btNode()
                  {
                                info = 0;
                                lt = null;
                                rt = null;
                  } 
          }
}

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I dont know if you need this, but its the main method I wrote

Code:

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import java.util.Scanner;

public class Intcoll6testclient
{
        public static final int SENTINEL = 0;
       
        public static void main(String[] args)
        {
                int value;
                int val2;
                Scanner keyboard=new Scanner(System.in);
            Intcoll6 P = new Intcoll6();
           
            System.out.println("Enter an integer to be inserted or 0 to quit:");
            value=keyboard.nextInt();
           
            while(value != SENTINEL)
            {
                    P.insert(value);
                   
                    System.out.println("Enter next integer to be inserted or 0 to quit:");
                    value=keyboard.nextInt();
            }
           
            System.out.println("Type a value to see if it belongs in the collection: ");
            val2 = keyboard.nextInt();
            System.out.println("The Method returned: " + P.belongs(val2));

        }
}

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Check your very last else-statement in your insert( ... ) method; why are your changing the root (c) of your tree when a value is already present in the tree?

kind regards,

Jos

The reason why I did that is so that c would get all of p's attributes. I tried to remove the else statement, but the belongs method still isnt working right, any more suggestions?

thanks

Never mind I figured out what I was doing wrong.

Thanks for the help

Quote:

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Originally Posted by Get_tanked

The reason why I did that is so that c would get all of p's attributes. I tried to remove the else statement, but the belongs method still isnt working right, any more suggestions?

thanks

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Variable c is the root of your tree, you can't set it to any arbitrary node. About more suggestions: why don't you use a TreeSet? It is implemented as a red-black tree which is exactly what you want. Or do you have to implement your own tree?

kind regars,

Jos