Input Output Examples

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Solution

import java.io.*;

/**
 * Example 141 - Input-Output: Twelve Examples in One
 */
class InputOutputExamples {
    public static void main(String[] args) throws IOException, ClassNotFoundException {
        // Write numbers and words on file "f.txt" in a human-readable form

        PrintWriter pwr  = new PrintWriter(new FileWriter("f.txt"));
        pwr.print(4711);
        pwr.print(' ');
        pwr.print("cool");
        pwr.close();

        // Read numbers and words from human-readable text file "f.txt"
        StreamTokenizer stok = new StreamTokenizer(new FileReader("f.txt"));
        int tok = stok.nextToken();

        while (tok != StreamTokenizer.TT_EOF)  {
            System.out.println(stok.sval);
            tok = stok.nextToken();
        }

        // Write primitive values to a binary file "p.dat"

        DataOutputStream dos = new DataOutputStream(new FileOutputStream("p.dat"));
        dos.writeInt(4711);
        dos.writeChar(' ');
        dos.writeUTF("cool");
        dos.close();

        // Read primitive values from binary file "p.dat"

        DataInputStream dis = new DataInputStream(new FileInputStream("p.dat"));
        System.out.println(dis.readInt() + "|" + dis.readChar() + "|" + dis.readUTF());

        // Writing an object or array to binary file "o.dat"

        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("o.dat"));
        oos.writeObject(new int[] {2, 3, 5, 7, 11});
        oos.close();

        // Read objects or arrays from binary file "o.dat"
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("o.dat"));
        int[] ia = (int []) (ois.readObject());
        System.out.println(ia.toString());

        // Read and write parts of file "raf.dat" in arbitrary order
        RandomAccessFile raf = new RandomAccessFile("raf.dat", "rw");
        raf.writeDouble(3.1415);
        raf.writeInt(42);
        raf.seek(0);
        System.out.println(raf.readDouble() + " " + raf.readInt());

        // Read from a String s as if were a text file:
        Reader r = new StringReader("abc");
        System.out.println("abc: " + (char) r.read() + (char) r.read() + (char) r.read());

        // Write to a StringBuilder as if it were a text file:
        Writer sw = new StringWriter();
        sw.write('d');
        sw.write('e');
        sw.write('f');
        System.out.println(sw.toString());

        // Write characters to standard output and standard error

        System.out.println("std output");
        System.err.println("std error");

        // Read characters from standard input (the keyboard)

        System.out.println("Type some characters and press Enter:");

        BufferedReader bisr = new BufferedReader(new InputStreamReader(System.in));
        String response = bisr.readLine();
        System.out.println("You typed: " + response);

        // Read a byte from standard input (the keyboard)

        System.out.println("Type one character and press Enter: ");
        byte b = (byte)System.in.read();
        System.out.println("First byte of your input is: " + b);
    }
}
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