| xenop |
Sep 19th, 2006 4:48 AM |
Need help will bug: function parameter.
Question
Im having a problem figuring out why the parameter in the scram() function is always null. Then causing a null pointer exception in the for loop.
Purpose of program
This program is supposed to read in from a file of strings scramble the string and then try to find it in a dictionary file. Then split the string if its long enougth and find matching smaller strings.
Im using Eclipse 3.1 with jdk 6.1
I appriciate any help.
:
import java.io.*; // for BufferedReader
import java.util.*;
public class scramble {
public static void main(String[] args) throws IOException {
String fileName = "inputstrings.txt", wordString, input;
BufferedReader inFile = new BufferedReader(new FileReader(fileName));
wordString = inFile.readLine();
while (wordString != null) {
System.out.println("Input word: " + wordString);
ScrambleWord dummy = new ScrambleWord(wordString, "wordlist.txt");
dummy.OutputData();
wordString = inFile.readLine();
}
inFile.close();
}
}
class ScrambleWord {
private Random generator = new Random();
private String dictFile;
private String input;
private String scrWord;
private Vector tempVector = new Vector();
private String[] dictionaryArray;
ScrambleWord(String word, String fileName) throws IOException {
dictFile=fileName;
input = word;
scram(input);
BufferedReader inFile =
new BufferedReader(new FileReader(dictFile));
while(!(inFile.readLine()== null)){
tempVector.add(inFile.readLine());
}
String[] dictionaryArray = new String[tempVector.size()];
tempVector.copyInto(dictionaryArray);
this.dictionaryArray = dictionaryArray;
}
private void scram(String input){
String a = "";
System.out.println(input);
for (int i = 0 ;i < (input.length()-1);i++){
if (generator.nextBoolean())
a = input.charAt(i) + a;
else
a = a + input.charAt(i);
}
scrWord = a;
}
public void OutputData() {
//System.out.println("testS2 " + scrWord);
long start = System.currentTimeMillis();
// exit condition for while loop
boolean reportedSingle = false;
boolean reportedDouble = false;
boolean reportedTriple = false;
//loops for a the a set time or if the word has been found
String b;
while((System.currentTimeMillis()-start) < 60000 ){
//System.out.println(System.currentTimeMillis()-start);
b = search(input, dictionaryArray);
if (b == null ){
scram(b);
//System.out.println(scrWord + "not found");
}
else if (!reportedSingle){
System.out.println("single:" + b);
reportedSingle = true;
}
if (b.length() > 6 && !reportedDouble){
int mid = b.length() / 2;
String firstWord = b.substring(0, mid-1);
String secondWord =
b.substring(mid, b.length()-1);
scram(firstWord);
String c = scrWord;
scram(secondWord);
String d = scrWord;
if ((search(firstWord, dictionaryArray)== null ))
scram(firstWord);
else {
search(firstWord, dictionaryArray);
System.out.println("first word:" + firstWord);
}
if ((search(secondWord, dictionaryArray)== null ))
scram(secondWord);
else {
search(secondWord,
dictionaryArray);
System.out.println("first word:" + firstWord);
}
}
reportedDouble = true;
}
}
static String search(String targetWord, String[] sArray){
//System.out.println("index: "+ (sArray.length-1) );
return searchHelper(targetWord, sArray, 0, (sArray.length-1));
}
static String searchHelper(String targetWord,
String[] sArray, int low, int high){
String rtn;
if (low > high){
rtn = null;
}
else{
int middle = (low + high) / 2;
if(sArray[middle].equals(targetWord))
rtn = sArray[middle];
else if (sArray[middle].compareTo(targetWord) < 0)
rtn = searchHelper(targetWord, sArray, middle+1, high);
else
rtn = searchHelper(targetWord, sArray, low, middle - 1);
}
return rtn;
}
}
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