[JAVA] Using a printwriter in an AVL tree - Tilted Forum Project - TFP - Sexuality, Philosophy and Political Discussion

89transam · 05-01-2005, 02:03 PM

Yes this is homework, but this is not supposed to be the part that trips us up.

The goal is to print an AVL tree in order to a file. I chose to go with a printwriter because it deals with strings easilly. I can get the correct output to a regular System.out command , but I cannot translate that to a file.

I know that the problem is that every time I call the getTreeInfo method recursivly I am creating a new instance of my file and print writers and it is just overwriting the same data, but I cant think of a way around this. Any help would be awesome. I dont want code , just any nudge in the right direction. ( I know this should be simple)

Code:

             

private void getTreeInfo( AvlNode t ) throws IOException
        {           
            	FileWriter writer = new FileWriter("output.txt");
            	PrintWriter out = new PrintWriter(writer);

            if( t != null )
            {
                getTreeInfo(t.left);          
                out.println(nodeInfo(t));
                out.println("\t" + "Left: " + "\t" + nodeInfo(t.left));
                out.println("\t" + "Right: " + "\t" + nodeInfo(t.right));
                getTreeInfo(t.right);                                               
            }
        	out.close();
        }

a-j · 05-01-2005, 08:28 PM

Just create the writer before calling getTreeInfo and pass the writer to the method:

Code:

private void getTreeInfo( AvlNode t, Writer out) throws IOException

Then adjust your recursive calls to getTreeInfo(t.left, out), and symmetrically for the right side.

SiNai · 05-01-2005, 09:37 PM

What he said

89transam · 05-02-2005, 11:12 PM

Yeah i ended up getting it. Just had to sleep on it, Thanks for the help though

05-01-2005, 02:03 PM	#1 (permalink)
89transam Psycho Join Date: Apr 2003 Location: Central California	[JAVA] Using a printwriter in an AVL tree Yes this is homework, but this is not supposed to be the part that trips us up. The goal is to print an AVL tree in order to a file. I chose to go with a printwriter because it deals with strings easilly. I can get the correct output to a regular System.out command , but I cannot translate that to a file. I know that the problem is that every time I call the getTreeInfo method recursivly I am creating a new instance of my file and print writers and it is just overwriting the same data, but I cant think of a way around this. Any help would be awesome. I dont want code , just any nudge in the right direction. ( I know this should be simple) Code: private void getTreeInfo( AvlNode t ) throws IOException { FileWriter writer = new FileWriter("output.txt"); PrintWriter out = new PrintWriter(writer); if( t != null ) { getTreeInfo(t.left); out.println(nodeInfo(t)); out.println("\t" + "Left: " + "\t" + nodeInfo(t.left)); out.println("\t" + "Right: " + "\t" + nodeInfo(t.right)); getTreeInfo(t.right); } out.close(); } __________________ I'd rather be rich than stupid. Last edited by 89transam; 05-01-2005 at 02:07 PM.

05-01-2005, 08:28 PM	#2 (permalink)
a-j Tilted Join Date: Sep 2004	Just create the writer before calling getTreeInfo and pass the writer to the method: Code: private void getTreeInfo( AvlNode t, Writer out) throws IOException Then adjust your recursive calls to getTreeInfo(t.left, out), and symmetrically for the right side.

05-01-2005, 09:37 PM	#3 (permalink)
SiNai Dreams In Digital Join Date: Oct 2003 Location: Iowa	What he said __________________ I can't seem to remember now What it was like- to live life, before you.. symbiont

05-02-2005, 11:12 PM	#4 (permalink)
89transam Psycho Join Date: Apr 2003 Location: Central California	Yeah i ended up getting it. Just had to sleep on it, Thanks for the help though __________________ I'd rather be rich than stupid.