03-Writing-Console-Output.md

Writing Console Output

Console output is most easily accomplished with print() and println(), described earlier, which are used in most of the examples in this book. These methods are defined by the class PrintStream (which is the type of object referenced by System.out).

Because PrintStream is an output stream derived from OutputStream, it also implements the low-level method write(). Thus, write() can be used to write to the console.

Example 01

// Demonstrate System.out.write().
class WriteDemo {
    public static void main(String args[]) {
        int b;
        b = 'A';
        System.out.write(b);
        System.out.write('\n');
    }
}

Output

A

The PrintWriter Class

For realworld programs, the recommended method of writing to the console when using Java is through a PrintWriter stream. PrintWriter is one of the character-based classes. Using a character-based class for console output makes internationalizing your program easier.

PrintWriter(OutputStream outputStream, boolean flushingOn)

To write to the console by using a PrintWriter, specify System.out for the output stream and automatic flushing.

Example 02

// Demonstrate PrintWriter
import java.io.*;
public class PrintWriterDemo {
    public static void main(String args[]) {
        PrintWriter pw = new PrintWriter(System.out, true);
        pw.println("This is a string");
        int i = -7;
        pw.println(i);
        double d = 4.5e-7;
        pw.println(d);
    }
}

Output

This is a string
-7
4.5E-7

External Resources

Readings

• JavaTPoint
• GeeksForGeeks - Formated Output

More Examples and Practice Questions

Provided in the last chapter of current section.