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POInfinite Recursion, StackOverError in huffman tree
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  1. POInfinite Recursion, StackOverError in huffman tree
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    copied!<p>I am working on a Huffman Encoding program and I am almost finished but I am stuck in an infinite recursion loop. Does anyone have an idea where this is going wrong? </p> <p>This is the error I am getting:</p> <pre><code>Exception in thread "main" java.lang.StackOverflowError at sun.nio.cs.SingleByteEncoder.encodeLoop(SingleByteEncoder.java:130) at java.nio.charset.CharsetEncoder.encode(CharsetEncoder.java:544) at sun.nio.cs.StreamEncoder.implWrite(StreamEncoder.java:252) at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:106) at java.io.OutputStreamWriter.write(OutputStreamWriter.java:190) at java.io.BufferedWriter.flushBuffer(BufferedWriter.java:111) at java.io.PrintStream.write(PrintStream.java:476) at java.io.PrintStream.print(PrintStream.java:619) at java.io.PrintStream.println(PrintStream.java:756) at HuffmanNode.buildTree(hw4.java:63) at HuffmanNode.buildTree(hw4.java:64) at HuffmanNode.buildTree(hw4.java:64) at HuffmanNode.buildTree(hw4.java:64) at HuffmanNode.buildTree(hw4.java:64) at HuffmanNode.buildTree(hw4.java:64) at HuffmanNode.buildTree(hw4.java:64) at HuffmanNode.buildTree(hw4.java:64) </code></pre> <p>and the output is continually 5:1, 5:4, 5:2, repeating</p> <p>my datafile looks like this:</p> <pre><code>a a a a d d d d d d d d k k k k k k f f f f f f h h h h h h b b b b b b b b n n n n n n n e e e e e i i i i i i i i l k j a n s g l k j a s v o i j a s d l k g k n m a s d k l o v h a s d g z </code></pre> <p>and my code is </p> <pre><code> import java.util.*; import java.io.*; class HuffmanNode implements Comparable&lt;HuffmanNode&gt;{ HuffmanNode right; HuffmanNode left; HuffmanNode parent; int count; String letter; public HuffmanNode(){} public HuffmanNode (String letter, int count){ this.letter = letter; this.count = count; } public HuffmanNode (String letter, int count, HuffmanNode parent, HuffmanNode left, HuffmanNode right){ this.letter = letter; this.count = count; this.left = left; this.right = right; this.parent = parent; } public void setCount(int count){ this.count = count; } public int getCount(){ return count; } public void setRight(HuffmanNode right){ this.right = right; } public HuffmanNode getRight(HuffmanNode right){ return right; } public void setLeft(HuffmanNode left){ this.left = left; } public HuffmanNode getLeft(HuffmanNode left){ return left; } public void setParent(HuffmanNode right){ this.left = left; } public HuffmanNode getParent(HuffmanNode parent){ return parent; } public void buildTree(HuffmanNode node){ if (node.compareTo(this) &lt;= 0 &amp;&amp; left != null){ System.out.println(node.getCount() + ":" + this.count); left.buildTree(node); } else if (node.compareTo(this) &lt;= 0 &amp;&amp; left == null){ this.left = node; node.parent = this; } else if (node.compareTo(this) &gt; 0 &amp;&amp; right != null){ System.out.println(node.getCount() + ":" +this.count); right.buildTree(node); } else if (node.compareTo(this) &gt; 0 &amp;&amp; right == null){ this.right = node; node.parent = this; } } public int compareTo(HuffmanNode x){ return this.count - x.count; } public void genCode(String s){ if(left != null){ left.genCode(s + "0"); } if(right != null){ right.genCode(s + "1"); } if (left == null &amp;&amp; right == null){ System.out.println(s); } } } public class hw4{ public static void main (String []args)throws IOException{ //ask user to enter file name System.out.printf("Enter a file location and name to encode [press Enter]: "); Scanner input = new Scanner(System.in); String filename = input.next(); //Gets file name from Scanner and checks to see if valid File file = new File(filename); //if (!file.isFile()){ //System.out.printf("Enter a file location and name to encode [press Enter]: "); //} Scanner text = new Scanner(file); String[] letters = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"}; int[] freq = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; String letter; String tempStr; int tempInt; while(text.hasNext()){ letter = text.next(); //System.out.printf("%s\n", letter); char c = letter.charAt(0); int index = c - 97; freq[index]++; } for(int i=0; i &lt;25; i++){ System.out.printf("%s:%d\n", letters[i], freq[i]); } System.out.printf("\n"); for (int n=0; n &lt;25; n++) { for (int i=0; i &lt;25; i++) { if (freq[i] &gt; freq[i+1]) { // exchange elements tempInt = freq[i]; tempStr = letters[i]; freq[i] = freq[i+1]; letters[i] = letters[i+1]; freq[i+1] = tempInt; letters[i+1] = tempStr; } } } PriorityQueue&lt;HuffmanNode&gt; huffmanList = new PriorityQueue&lt;HuffmanNode&gt;(); for(int i=0; i &lt;26; i++){ System.out.printf("%s:%d\n", letters[i], freq[i]); if(freq[i] &gt; 0){ huffmanList.add(new HuffmanNode(letters[i],freq[i])); } } HuffmanNode root = new HuffmanNode(); while(huffmanList.size() &gt; 1){ HuffmanNode x = huffmanList.poll(); HuffmanNode y = huffmanList.poll(); HuffmanNode result = new HuffmanNode("-", x.getCount() + y.getCount(), null, x, y); if(root == null){ root = result; } else{ root.buildTree(result); } huffmanList.add(result); } root.genCode(" "); } } </code></pre>
 

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