Chapter 10

import java.io.*;

public class IO {

	IO() {
		create(3, sFile1);
		create(4, sFile2);
		try {
			boolean bFlag = false;
			BufferedReader br1 = 
				new BufferedReader(
					new FileReader(sFile1));
			BufferedReader br2 = 
				new BufferedReader(
					new FileReader(sFile2));
			PrintWriter os = 
				new PrintWriter(
					new 
				  FileOutputStream(sFile3));
			while (true) {
				String sLine =
					br1.readLine();
				if (sLine == null || 
					sLine.length() <= 0)
					break;
				int nValue1 = 
					Integer.parseInt(sLine);
				sLine = br2.readLine();
				if (sLine == null ||
					sLine.length() <= 0)
					break;
				int nValue2 = 
					Integer.parseInt(sLine);
				os.print(" " + 
					((bFlag = !bFlag) ?
						nValue1 : nValue2));
			}
			os.close();
		} catch (IOException e) {
			System.out.println(
					"IO Exception: " + e);
		}
	}

	private void create(int n, String sFile) {
		try {
			PrintWriter os = 
				new PrintWriter(
					new
				   FileOutputStream(sFile));
			int n2 = n * n;
			for (int i=-n2; i<=n2; i+= n)
				os.println(i);
			os.close();
		} catch (IOException e) {
			System.out.println(
					"IOException: " + e);
		}
	}

	private String sFile1 = "Data1.txt";
	private String sFile2 = "Data2.txt";
	private String sFile3 = "Data3.txt";

	public static void main(String[] args) {
		new IO();
	}

}

import java.io.*;

public class IO {

	IO() {
		try {
			ObjectOutputStream os = 
				new ObjectOutputStream(
					new FileOutputStream(sFile));
			for (char c='A'; c<'K'; ++c)
				os.writeChar(c);
			os.close();
			ObjectInputStream is = 
				new ObjectInputStream(
					new FileInputStream(sFile));
			while (true) {
				char c = is.readChar();
				is.readChar();
				System.out.print(c);
			}
		} catch (EOFException e) {
			System.out.println();
		} catch (IOException e) {
			System.out.println(
					"IOException: " + e);
		}
	}

	private String sFile = "Data.txt";

	public static void main(String[] args) {
		new IO();
	}

}

import java.io.*;

public class IO {

	final String FILE = "data.txt";

	IO() {
		write();
		read();
	}

	void write() {
		try {
			PrintWriter pw =
				new PrintWriter(
					new FileWriter(FILE));
			for (int n = 1; n <= 4; n++) {
				pw.print(n + ".");
				for (int k = 0; k < n; k++)
					pw.print(n);
				pw.println();
			}
			pw.println();
			pw.close();
		} catch (IOException e) {
			System.err.println(
				"Couldn't create " + FILE);
		}
	}

	void read() {
		try {
			String line;
			double result = 0, value;
			BufferedReader br =
				new BufferedReader(
					new FileReader(FILE));
			while ((line = br.readLine()).
					compareTo("") != 0) {
				System.out.println(
					"[" + line + "]");
				value =
				   Double.parseDouble(line);
				result += value;
			}
			br.close();
			System.out.println(result);
		} catch (IOException e) {
			System.err.println(
				"Couldn't read " + FILE);
		}
	}

	public static void main(String[] args) {
		new IO();
	}
}

import java.io.*;

public class IO {

	IO(int n) {
		PrintWriter os = null;
		for (int i=0; i<3; i++) {
			try {
				os = new PrintWriter(
                 new FileOutputStream(sFile,
                 i >= 1));
				os.println("n=" + n + 
                           "   i=" + i);
				os.close();
			} catch (FileNotFoundException e) {
				System.out.println("File not found: " + e);
			}
		}
	}

	private String sFile = "Test.txt";

	public static void main(String[] args) {
		new IO(1);
		new IO(2);
	}

}

import java.io.*;

class Info implements Serializable {
	private String s;
	private char   c;
	private int    n;
	Info(String ss, char cc, int nn) {
		s = ss;  c = cc;  n = nn;
	}
	public String toString() {
		return s + " | " + c + " | " + n;
	}
}

public class IO {

	final String FILE = "data.txt";

	IO() {
		write();
		read();
	}

	void write() {
		Info info1= new Info("Abc", 'x', 1);
		Info info2= new Info("Def", 'y', 2);
		Info info3= new Info("Ghi", 'z', 3);
		try {
			ObjectOutputStream os =
			  new ObjectOutputStream(
				new FileOutputStream(FILE));
			os.writeObject(info3);
			os.writeObject(info1);
			os.writeObject(info2);
		} catch (IOException e) {
			System.err.println(
				"Output Error: " + FILE);
		}
	}

	void read() {
		Info info;
		try {
			ObjectInputStream is = 
			  new ObjectInputStream(
				new FileInputStream(FILE));
			while (true) {
				info =
					(Info) is.readObject();
				System.out.println(info);
			}
		} catch (EOFException e) {
		} catch (IOException e) {
			System.err.println(
				"Input error: " + FILE);
		} catch (ClassNotFoundException e) {
			System.err.println(
				"Class error: " + FILE);
		}
	}

	public static void main(String[] args) {
		new IO();
	}
}

import java.io.*;

class Info implements Serializable {
	private String s;
	private char   c;
	private transient int n;
	Info(String ss, char cc, int nn) {
		s = ss;  c = cc;  n = nn;
	}
	public String toString() {
		return s + " | " + c + " | " + n;
	}
}

public class IO {

	final String FILE = "data.txt";

	IO() {
		write();
		read();
	}

	void write() {
		Info info1= new Info("Abc", 'x', 7);
		Info info2= new Info("Def", 'y', 8);
		Info info3= new Info("Ghi", 'z', 9);
		try {
			ObjectOutputStream os =
			  new ObjectOutputStream(
				new FileOutputStream(FILE));
			os.writeObject(info2);
			os.writeObject(info1);
			os.writeObject(info3);
		} catch (IOException e) {
			System.err.println(
				"Output Error: " + FILE);
		}
	}

	void read() {
		Info info;
		try {
			ObjectInputStream is = 
			  new ObjectInputStream(
				new FileInputStream(FILE));
			while (true) {
				info =
					(Info) is.readObject();
				System.out.println(info);
			}
		} catch (EOFException e) {
		} catch (IOException e) {
			System.err.println(
				"Input error: " + FILE);
		} catch (ClassNotFoundException e) {
			System.err.println(
				"Class error: " + FILE);
		}
	}

	public static void main(String[] args) {
		new IO();
	}
}

import java.io.*;

public class IO {

	IO() {
		float[] flt = { 3, 1, 4, 1, 
						5, 9, 6, 8 };
		create(flt);
		display();
	}

	private void create(float[] flt) {
		try {
			ObjectOutputStream os =
			  new ObjectOutputStream(
				new FileOutputStream(
						sFile));
			os.writeObject(flt);
			os.close();
		} catch (IOException e) {
			System.out.println(
					   "IOException: " + e);
		}
	}

	private void display() {
		try {
			ObjectInputStream is =
			  new ObjectInputStream(
				new FileInputStream(sFile));
			float[] flt = (float[]) 
							is.readObject();
			is.close();
			for (int i=0; i

import java.io.*;

public class IO {

	IO() {
		int nValue = 0;
		try {
			PrintWriter os = null;
			os = new PrintWriter(
               new FileOutputStream(sFile));
			for (int i=1; i<6; i++)
			os.println(i * i);
			os.close();
			BufferedReader br = 
               new BufferedReader(
                   new FileReader(sFile));
			while (true) {
				String 
                    sLine = br.readLine();
				if (sLine == null ||
                    sLine.length() <= 0)
					break;
				nValue += Integer.
                            parseInt(sLine);
			}
		} catch (FileNotFoundException e) {
			System.out.println(
                    "File not found: " + e);
		} catch (IOException e) {
			System.out.println(
                    "IO Exception");
		}
		System.out.println("nValue=" +
                           nValue);
	}

	private String sFile = "Data.txt";

	public static void main(String[] args) {
		new IO();
	}

}

import java.io.*;

public class IO {

	IO() {
		long inc = create(4);
		display(inc);
	}

	private long create(final int n) {
		long inc = 0;
		try {
			RandomAccessFile ios = 
				new RandomAccessFile(sFile,
									 "rw");
			ios.setLength(0);
			double d = 1.1;
			for (int i=0; i= 0) {
				double d = ios.readDouble();
				System.out.print(d + "  ");
				if ((loc -= inc) >= 0)
					ios.seek(loc);
			}
			ios.close();
			System.out.println();
		} catch (IOException e) {
			System.out.println(
					   "IOException: " + e);
		}
	}

	private String sFile = "Data.dat";

	public static void main(String[] args) {
		new IO();
	}

}

import java.io.*;

public class IO {

	IO() {
		final String FILE = "data.txt";

		try {
			PrintWriter pw =
				new PrintWriter(
					new FileWriter(FILE));
			for (int n = 1; n < 7; n++)
				pw.print(" " + n);
			pw.println();
			pw.close();
		} catch (IOException e) {
			System.err.println(
				"Couldn't create " + FILE);
		}
	}

	public static void main(String[] args) {
		new IO();
	}
}

1. The principal difference between InputStreams and Readers is in the amount of processing that each does.
2. The principal difference between OutputStreams and Writers is in the amount of processing that each does.
3. Character streams deal with ASCII characters.
4. Byte streams deal with Unicode bytes.
5. System.in, System.out, System.error are the three predefined standard I/O streams.

1. The length of a file opened using RandomAccessFile is set to zero
2. When you open a RandomAccessFile, the file pointer is set to the beginning of the file
3. When you open a RandomAccessFile, the file pointer is set to the end of the file, ready for a write operation
4. You can effectively empty a RandomAccessFile by using the setLength method

When reading beyond the end of file in the case of a text file, using BufferedReader:

1. an EOFException always is thrown
2. an EOFException never is thrown

When reading beyond the end of file in the case of a binary file:

3. an EOFException always is thrown
4. an EOFException never is thrown