Number format exception

Can any one pls fix dis runtime error

/* Dealing with binary data:
Create a program to read a list of floating point numbers in a text
file and then write the data to a binary file.
 (Use classes: FileReader, FileBufferedReader, FileOutputStream,
String, Float, DataOutputStream).
Note:
Use FileReader and FileBufferedReader classes to be able to read each
line of the file as a string. Use split method of String class to
break the line into words.
Use Float.parseFloat to convert the string to floating point number.
Use FileOutputStream and DataOutputStream to write the float data as a
binary data to the file.
*/

import java.io.*;
import java.util.regex.*;

public class readfloat {
  public static void main(String args[]) throws IOException {

    FileReader fr = new FileReader("input.txt");
    BufferedReader br = new BufferedReader(fr);
    String s;

    Pattern pat = Pattern.compile(", ");

    FileOutputStream fout = new FileOutputStream("output.txt");
    DataOutputStream out = new DataOutputStream(fout);
    while((s = br.readLine())!=null) {
        String str[] = pat.split(s);
        for(int i=0;i<str.length;i++){
            float f = Float.parseFloat(str[i]);
            out.writeFloat(f);
        }
    }
    fr.close();
    out.close();
  }
}