file - Read streamfile in java -

i working on comma separated value file.i want extract first position["0" place in array] value each raw , want math calculation on it.

csv inputfile a,b,c,d 12,32,45,76 23,45,77,56 32,34,49,28 73,92,26,68 73,36,77,26 

for getting first position give me error this

exception in thread "main" java.lang.numberformatexception: input string: ""12" @ sun.misc.floatingdecimal.readjavaformatstring(floatingdecimal.java:1268)  @ java.lang.double.parsedouble(double.java:548)     @ rotation.pkg45.rotation45.main(rotation45.java:49)//code line no-49 

it work fine second , third position fourth give same error first.

 package rotation.pkg45;import java.io.file; import java.io.filenotfoundexception; import java.util.scanner; import java.util.logging.level; import java.util.logging.logger; import java.io.filewriter; import java.io.*; import java.text.decimalformat; import java.util.arraylist; import java.util.collections; import java.util.list; import java.util.listiterator; public class rotation45 {  public static void main(string[] args)throws ioexception {         string filename = "bank-full2.csv";         arraylist<string> nameslist = new arraylist<string>( );         string[] t1;        // stringbuilder sb;         list<double> list = new arraylist<double>();         file file = new file(filename);         bufferedwriter writer = null;          try {             writer = new bufferedwriter(new filewriter("bank2test1.csv"));                     double a1=0.866025;         double a2=0.5;         double a3=-0.5;         double a4=0.866025;         double b1;         double b2;         double c1;         double c2;                        scanner inputstream = new scanner(file);             inputstream.next();                scanner inputstreamm = new scanner(file);             inputstreamm.next();                     while (inputstreamm.hasnext()) {   //while loop find mean             string data = inputstreamm.next();   //read each line , store in data             string[] values = data.split(",");  //every line splited " ; " , store each attribute in string list               double first = double.parsedouble(values[1]);              /* no suchelementexeption  */  string data1 = inputstreamm.next();   //read each line , store in data             string[] values1 = data1.split(",");               //inputstream.next();                       double second = double.parsedouble(values1[1]);               c1= ((a2*second)+(a1*first));     c2= ((a3*first)+(a4*second));        values1[2] = string.valueof(c2);         values[2] = string.valueof(c1);        stringbuilder sb = new stringbuilder();             //  string newdata = sb.tostring();             (int = 0; i<values.length ; i++) {                     sb.append(values[i]);                     if (i < values.length - 1) {                     sb.append(",");                 }                     }              sb.append("\n");               (int = 0; i<values1.length ; i++) {                     sb.append(values1[i]);                     if (i < values.length - 1) {                     sb.append(",");                 }                     }             // new string            // system.out.println(sb.tostring());              writer.write(sb.tostring()+"\n");                 }             writer.close();              inputstreamm.close();               }         catch (filenotfoundexception ex)               {             logger.getlogger(rotation45.class.getname()).log(level.severe, null, ex);         }      } }               

here example had extracted values[1](means second position in array 32,45,34,..)

so result be.. 12,34,45,76 23,46,77,56 32,36,49,28 73,93,26,68 73,38,77,26 

this codeis works values[1]and value[2] not in values[0]and value[3]..why cant understand pls me...

there problem in code in terms of generating exception , readability.

i rewrote code , working :

package rotation.pkg45;  import java.io.bufferedwriter; import java.io.file; import java.io.filenotfoundexception; import java.io.filewriter; import java.io.ioexception; import java.util.scanner; import java.util.logging.level; import java.util.logging.logger;  public class rotation45 {     public static void main(string[] args) throws ioexception {         string filename = "bank-full2.csv";         file file = new file(filename);         bufferedwriter writer = null;          try {             writer = new bufferedwriter(new filewriter("bank2test1.csv"));              scanner inputstreamm = new scanner(file);             inputstreamm.nextline();              while (inputstreamm.hasnext()) { // while loop find mean                 string data = inputstreamm.nextline(); // read each line , store in data                 string[] values = data.split(","); // every line splited " , " , store each attribute in string list                  // double value generating 34.0 value, , expecting 34                 // double first = double.parsedouble(values[1]);                 int first = integer.parseint(values[1]);                 first = first + 2;                  values[1] = string.valueof(first);                 stringbuilder sb = new stringbuilder();                 // string newdata = sb.tostring();                 (int = 0; < values.length; i++) {                     sb.append(values[i]);                     if (i < values.length - 1) {                         sb.append(",");                     }                 }                  if (inputstreamm.hasnext()) { /* handle nosuchelementexception */                     string data1 = inputstreamm.nextline(); // read each line , store in data                     string[] values1 = data1.split(",");                      // double second = double.parsedouble(values1[1]);                     int second = integer.parseint(values1[1]);                     second = second + 1;                     values1[1] = string.valueof(second);                      sb.append("\n");                     (int = 0; < values1.length; i++) {                         sb.append(values1[i]);                         if (i < values.length - 1) {                             sb.append(",");                         }                     }                 }                 writer.write(sb.tostring() + "\n");             }             writer.close();              inputstreamm.close();          } catch (filenotfoundexception ex) {             logger.getlogger(rotation45.class.getname()).log(level.severe, null, ex);         }     } } 

csv input file:

a,b,c,d 12,32,45,76 23,45,77,56 32,34,49,28 73,92,26,68 73,36,77,26 

csv output file:

12,34,45,76 23,46,77,56 32,36,49,28 73,93,26,68 73,38,77,26 

---

changes done are:

1. replaced inputstreamm.next(); inputstreamm.nextline();
2. code refactored. processing of values done first , values1.
3. added if (inputstreamm.hasnext()) handle nosuchelementexception.
4. replaced double.parsedouble(values1[1]); integer.parseint(values1[1]);, generating 34.0 , wanted 34 in output file.