Demo program in tutorial can't give out expected result

Question

I run DataIODemo.java from java tutorial
The output file has below content
@3�p��
=           J a v a T - s h i r t
@#��G�{                J a v a   M u g
@/��G�{        
     D u k e J u g g l i n g D o l l s
@���Q�           J a v a P i n
@���\(�      2      J a v a K e y C h a i n
It seems the program can't read long type values
Plz help
Below is the program's script
import java.io.*;
import java.lang.*;
public class iodemo {
public static void main(String[] args) throws IOException {
// write the data out
DataOutputStream out = new DataOutputStream(new
                    FileOutputStream("c:/numout.txt"));
double[] prices = { 19.99, 9.99, 15.99, 3.99, 4.99 };
int[] units = { 12, 8, 13, 29, 50 };
String[] descs = { "Java T-shirt",
               "Java Mug",
               "Duke Juggling Dolls",
               "Java Pin",
               "Java Key Chain" };
for (int i = 0; i < prices.length; i ++) {
out.writeDouble(prices);
out.writeChar('\t');
out.writeInt(units[i]);
out.writeChar('\t');
out.writeChars(descs[i]);
out.writeChar('\n');
out.close();
// read it in again
DataInputStream in = new DataInputStream(new
                    FileInputStream("c:/numout.txt"));
double price;
int unit;
StringBuffer desc;
double total = 0.0;
try {
while (true) {
price = in.readDouble();
                    System.out.println(price);
in.readChar(); // throws out the tab
unit = in.readInt();
in.readChar(); // throws out the tab
          char chr;
          desc = new StringBuffer(20);
          char lineSep = System.getProperty("line.separator").charAt(0);
          while ((chr = in.readChar()) != lineSep)
          desc.append(chr);
System.out.println("You've ordered " +
                    unit + " units of " +
                    desc + " at $" + price);
total = total + unit * price;
} catch (EOFException e) {
System.out.println("For a TOTAL of: $" + total);
in.close();

Answer 1

Try this,import java.io.*;
import java.lang.*;
import java.util.StringTokenizer;
public class iodemo {
     public static void main(String[] args) throws IOException {
          RandomAccessFile out = new RandomAccessFile("c:/test/numout.txt","rw");
          double[] prices = { 19.99, 9.99, 15.99, 3.99, 4.99 };
          int[] units = { 12, 8, 13, 29, 50 };
          String[] descs = { "Java T-shirt","Java Mug",
                              "Duke Juggling Dolls","Java Pin","Java Key Chain" };
          for (int i = 0; i < prices.length; i ++) {
               out.writeBytes(prices[i]+"\t");
               out.writeBytes(units[i]+"\t");
               out.writeBytes(descs[i]+"\n");
          out.close();
          // read it in again
          RandomAccessFile in = new RandomAccessFile("c:/test/numout.txt","r");
          double price;
          int unit;
          String desc;
          double total = 0.0;
          String line="";
          try {
               while ((line=in.readLine())!=null) {
                    StringTokenizer st = new StringTokenizer(line,"\t");
                    price = Double.parseDouble(st.nextToken());
                    unit = Integer.parseInt(st.nextToken());
                    desc = st.nextToken();
                    System.out.println("You've ordered " + unit + " units of " +
                         desc + " at $" + price);
                    total = total + unit * price;
          } catch (EOFException e) {
          System.out.println("For a TOTAL of: $" + total);
          in.close();
}Sudha