File Input and Output Stream

import java.io.*;

    class FileIO {
    
         public static void main(String[] args) {
        
         System.out.println("Enter some numbers.");
         StreamTokenizer st = new StreamTokenizer(
         new BufferedReader(new InputStreamReader(System.in)));
         File f = new File("temp.out");
         int numberCount = 0;
             try {
             DataOutputStream dos = new DataOutputStream(
             new BufferedOutputStream(new FileOutputStream(f)));
                 while (st.nextToken() != st.TT_EOF) {
                     if (st.ttype == st.TT_NUMBER) {
                     dos.writeDouble(st.nval);
                     numberCount++;
                 }
             }
             System.out.println("numberCount=" + numberCount);
             dos.flush();
             dos.close();
             DataInputStream dis = new DataInputStream(
             new BufferedInputStream(new FileInputStream(f)));
                 for (int i = 0; i < numberCount; i++) {
                 System.out.println("number=" + dis.readDouble());
             }
             dis.close();
             } catch (IOException e) {
             System.err.println("FileIO: " + e);
             } finally {
             f.delete();
         }
     }
}

/* ............... Example compile and run(s)

% javac file.java

% java FileIO
Enter some numbers.
1 2 3
4.4 5.5
6.67
^D
numberCount=6
number=1.0
number=2.0
number=3.0
number=4.4
number=5.5
number=6.67
... end of example run(s) */