Need help with Binary Search Tree

midnight_blue — Mon, 30 Oct 2006 21:24:36 +0800

I'm doing an assignment on a basic spell checker, and I'm stuck at the part where I'm required to have a binary search tree to store the words (a small dictionary).

[Problem 1]
To my understanding, the insert method will arrange them alphabetically. But I couldn't figure out how to find the words lying next to a target word.

If a word is not found in the dictionary, it's supposed to return the words exactly next to it. So I have a method findImmediate(String wrongWord) that returns a Queue. Say if wrongWord is "icee", the Queue will contain the words "ice" and "ices".

How should I manipulate the binary search tree to do that?

[Problem 2]
Another part is to write the words in the binary search tree to a text file. Is it correct for me to do this? :

CODE

public void toFile() {
if (!bst.isEmpty()) {
bst.depthFirstTraversal( new AbstractPrePostVisitor() {
public void inVisit(Object obj) {
try {
BufferedWriter bw = new BufferedWriter(new FileWriter("newWords.txt"));
bw.write(((Str)obj).stringValue());
}
catch (IOException ioe) {
System.out.println("Error writing to newWords.txt..");
}
}
} );
}
}

Doesn't seem to work; the text file is empty, even though the System.out.println() works fine in the inVisit().

I'd really appreciate some guide, thanks!

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Need help with Binary Search Tree