Thread: Arranging words in a sentence in alphabatical order.

Each sentence begins with a space. Gettin a null pointer exception at line 55. Plez help.

import java.io.*;
 
public class sent5 {
	String temp = "";
	String x;
	String x1; // to store each word of sentence
	String c;
	int l; // length of string
	int i;
	int l1; // length of sentence
	int c1;
	int k = 0; // array variable
 
	public void test() throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		System.out.println("ENTER SENTENCE");
		x = br.readLine();
		x += " ";
		l = x.length();
		for (i = 0; i < l; i++) {
			if ((x.charAt(i) != '.') && (x.charAt(i + 1) != ' '))
				c += x.charAt(i);
			else
				sent(c);
		}
	}
 
	public void sent(String c) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		l1 = c.length();
		for (i = 0; i < l1; i++) {
			if (x.charAt(i) == ' ')
				c1++;
		}
		String v[] = new String[c1];
		for (i = 0; i < l1; i++) {
			if (c.charAt(i) != ' ')
				x1 += c.charAt(i);
			else {
				v[k] = x1;
				k++;
				x1 = null;
			}
		}
		for (int i = 0; i < c1 - 1; i++) {
			for (int j = 0; j < c1 - i - 1; j++) {
				if (v[j].compareToIgnoreCase(v[j + 1]) > 0) {
					temp = v[j];
					v[j] = v[j + 1];
					v[j + 1] = temp;
				}
			}
		}
 
		// print
	}
 
	public static void main(String args[]) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		sent5 o1 = new sent5();
		o1.test();
	}
}

Which line is line 55? Where is your stack trace?

When posting code, please use the code or highlight tags. I did it for you this time, but please be more mindful in the future. You should probably edit your post and fix the indentation.

I've fixed the indentations as I compiled the code. As Kevin says, please do this yourself in future.

You have several issues but the first one starts here:

if (v[j].compareToIgnoreCase(v[j + 1]) > 0) {

Read up on the NullPointerException - http://download.oracle.com/javase/6/...Exception.html

If I were you I would remove everything else and concentrate on getting this part of the code to work before you move on.
Another tip would be to give your variables a more descriptive name. l, i, k, c1 etc makes things more complicated IMO