Re: DataInputStream
moongeegee wrote:
Would anyone please help me to understand why the return value ret is
-21 (a negative number 21)
Public static void (DataInputStream buf) {
DataInputStream dis = new DataInputStream(buf);
int ret = dis.available(); <=== here, the return value
ret = -21
}
The cause may be one of ...
A) You are doing something wrong in the code you are hiding from us.
B) It's only an estimate and estimates can be wrong.
C) There's a bug in some code you are using.
I am unable to reproduce your result:
--------------------------8<--------------------------
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
/*
* Author: RGB but based almost entirely on an older version of
* http://java.sun.com/docs/books/tutorial/essential/io/datastreams.html
*
*/
public class AvailableTest {
public static void main(String[] args) {
Double[] prices = { 1.1d, 2.2d, 3.3d };
Integer[] units = { 1, 2, 3 };
String[] descs = { "One", "Two", "Three" };
DataOutputStream dos;
try {
dos = new DataOutputStream(
new FileOutputStream("invoice1.txt"));
for (int i = 0; i < prices.length; i++) {
dos.writeDouble(prices[i]);
dos.writeChar('\t');
dos.writeInt(units[i]);
dos.writeChar('\t');
dos.writeUTF(descs[i]);
dos.writeChar('\n');
}
dos.close();
} catch (IOException e) {
e.printStackTrace();
System.exit(1);
}
try {
DataInputStream dis =
new DataInputStream(
new FileInputStream("invoice1.txt"));
Double total = 0.0d;
try {
while (true) {
// ************************************************
System.out.println("Available=" + dis.available());
// ************************************************
Double price = dis.readDouble();
dis.readChar(); // throws out the tab
Integer unit = dis.readInt();
dis.readChar(); // throws out the tab
String desc = dis.readUTF();
dis.readChar(); // throws out the newline ?
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);
dis.close();
}
} catch (IOException e) {
e.printStackTrace();
System.exit(1);
}
}
}
--------------------------8<--------------------------
Perhaps you can post an SSCCE (http://sscce.org) that demonstrates your
problem?
--
RGB