import java.io.*;
public class WriteToFile{
	public static void main(String [ ] args) throws IOException{
		//WRITING TO FILE
		FileOutputStream fos = new FileOutputStream ( "f.dat");
		BufferedOutputStream bos = new BufferedOutputStream(fos);
		DataOutputStream dos = new DataOutputStream(bos);
		dos.writeInt(30);
		dos.close( );
		//READING FROM FILE
		FileInputStream fis = new FileInputStream ("f.dat");
		BufferedInputStream bis = new BufferedInputStream(fis);
		DataInputStream dis = new DataInputStream(bis);
		int i = dis.readInt( );
		System.out.println( "Number read from file f:"+ i );
		dis.close();
	}
}