import java.util.Scanner;
import java.io.*;

public class DiskFileReadWrite
{
	public static void main(String[] args)
	{
		// The "line.separator" is used when writing 'newline' characters to
		//  disk text files, since using "\n" will not always cause lines to
		//  appear on new lines; for example, if using "\n", the files will
		//  look okay when displayed through a DOS prompt or with WordPad,
		//  but they will not look okay when viewed with Windows Notepad
		final String NL = System.getProperty("line.separator");

		String diskFile1 = "DemoFile1.txt";
		String diskFile2 = "DemoFile2.txt";
		String diskFile3 = "DemoFile3.txt";
		String line;
		int data;

		try
		{
			// Create a 'FileWriter' object
			FileWriter output1 = new FileWriter(diskFile1);
			output1.write("One" + NL); // Must manually write a 'newline' character
			output1.write("first", 0, 2); // Writes the first two characters ("fi")
			output1.close(); // Output will not be written until the file is closed

			// Create a 'BufferedWriter' object from a 'FileWriter' object
			BufferedWriter output2 = new BufferedWriter(new FileWriter(diskFile2));
			output2.write("Two" + NL); // Must manually write a 'newline' character 
			output2.write("second", 0, 3); // Writes the first three characters ("sec")
			output2.close(); // Output will not be written until the file is closed

			// Create a 'PrintWriter' object from a 'BufferedWriter' object from a 'FileWriter' object
			PrintWriter output3 = new PrintWriter(new BufferedWriter(new FileWriter(diskFile3)));
			output3.println("Three"); // Automatically writes a 'newline' character
			output3.write("third", 1, 2); // Writes the 2nd and 3rd characters ("hi")
			output3.close(); // Output will not be written until the file is closed


			// Create a 'FileReader' object to read from 'diskFile1'; a "-1" means 'end of file'
			FileReader input1 = new FileReader(diskFile1);
			data = input1.read(); // Reads the ASCII value of the first character ("O" = 79)
			System.out.println("From file #1, line #1:  " + data);
			data = input1.read(); // Read the ASCII value of the next character ("n" = 110) 
			System.out.println("From file #1, line #2:  " + data + "\n");
			input1.close();

			// Two approaches to creating a 'BufferedReader' object for reading from 'diskFile2'
			//BufferedReader input2 = new BufferedReader(new FileReader(new File(diskFile2)));
			BufferedReader input2 = new BufferedReader(new FileReader(diskFile2));
			line = input2.readLine();
			System.out.println("From file #2, line #1:  " + line);
			line = input2.readLine();
			System.out.println("From file #2, line #2:  " + line + "\n");
			input2.close();

			// Three approaches to creating a 'Scanner' object for reading from 'diskFile3'
			//Scanner input3 = new Scanner(new FileReader(new File(diskFile3)));
			//Scanner input3 = new Scanner(new FileReader(diskFile3));
			Scanner input3 = new Scanner(new File(diskFile3));
			line = input3.nextLine();
			System.out.println("From file #3, line #1:  " + line);
			line = input3.nextLine();
			System.out.println("From file #3, line #2:  " + line);
			input3.close();
		}
		catch (Exception error)
		{
			System.out.println("ERROR:  " + error.getMessage());
		}
	}
}