StdOut.java


Below is the syntax highlighted version of StdOut.java from § Standard Libraries.   Here is the Javadoc.


/******************************************************************************
 *  Compilation:  javac StdOut.java
 *  Execution:    java StdOut
 *  Dependencies: none
 *
 *  Writes data of various types to standard output.
 *
 ******************************************************************************/

import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.Locale;

/**
 *  <i>Standard output</i>. This class provides methods for writing strings
 *  and numbers to standard output.
 *  <p>
 *  For additional documentation, see <a href="http://introcs.cs.princeton.edu/15inout">Section 1.5</a> of
 *  <i>Introduction to Programming in Java: An Interdisciplinary Approach</i> by Robert Sedgewick and Kevin Wayne.
 *
 *  @author Robert Sedgewick
 *  @author Kevin Wayne
 */
public final class StdOut {

    // force Unicode UTF-8 encoding; otherwise it's system dependent
    private static final String CHARSET_NAME = "UTF-8";

    // assume language = English, country = US for consistency with StdIn
    private static final Locale LOCALE = Locale.US;

    // send output here
    private static PrintWriter out;

    // this is called before invoking any methods
    static {
        try {
            out = new PrintWriter(new OutputStreamWriter(System.out, CHARSET_NAME), true);
        }
        catch (UnsupportedEncodingException e) {
            System.out.println(e);
        }
    }

    // don't instantiate
    private StdOut() { }

   /**
     * Closes standard output.
     */
    public static void close() {
        out.close();
    }

   /**
     * Terminates the current line by printing the line-separator string.
     */
    public static void println() {
        out.println();
    }

   /**
     * Prints an object to this output stream and then terminates the line.
     *
     * @param x the object to print
     */
    public static void println(Object x) {
        out.println(x);
    }

   /**
     * Prints a boolean to standard output and then terminates the line.
     *
     * @param x the boolean to print
     */
    public static void println(boolean x) {
        out.println(x);
    }

   /**
     * Prints a character to standard output and then terminates the line.
     *
     * @param x the character to print
     */
    public static void println(char x) {
        out.println(x);
    }

   /**
     * Prints a double to standard output and then terminates the line.
     *
     * @param x the double to print
     */
    public static void println(double x) {
        out.println(x);
    }

   /**
     * Prints an integer to standard output and then terminates the line.
     *
     * @param x the integer to print
     */
    public static void println(float x) {
        out.println(x);
    }

   /**
     * Prints an integer to standard output and then terminates the line.
     *
     * @param x the integer to print
     */
    public static void println(int x) {
        out.println(x);
    }

   /**
     * Prints a long to standard output and then terminates the line.
     *
     * @param x the long to print
     */
    public static void println(long x) {
        out.println(x);
    }

   /**
     * Prints a short integer to standard output and then terminates the line.
     *
     * @param x the short to print
     */
    public static void println(short x) {
        out.println(x);
    }

   /**
     * Prints a byte to standard output and then terminates the line.
     * <p>
     * To write binary data, see {@link BinaryStdOut}.
     *
     * @param x the byte to print
     */
    public static void println(byte x) {
        out.println(x);
    }

   /**
     * Flushes standard output.
     */
    public static void print() {
        out.flush();
    }

   /**
     * Prints an object to standard output and flushes standard output.
     * 
     * @param x the object to print
     */
    public static void print(Object x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints a boolean to standard output and flushes standard output.
     * 
     * @param x the boolean to print
     */
    public static void print(boolean x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints a character to standard output and flushes standard output.
     * 
     * @param x the character to print
     */
    public static void print(char x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints a double to standard output and flushes standard output.
     * 
     * @param x the double to print
     */
    public static void print(double x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints a float to standard output and flushes standard output.
     * 
     * @param x the float to print
     */
    public static void print(float x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints an integer to standard output and flushes standard output.
     * 
     * @param x the integer to print
     */
    public static void print(int x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints a long integer to standard output and flushes standard output.
     * 
     * @param x the long integer to print
     */
    public static void print(long x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints a short integer to standard output and flushes standard output.
     * 
     * @param x the short integer to print
     */
    public static void print(short x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints a byte to standard output and flushes standard output.
     *
     * @param x the byte to print
     */
    public static void print(byte x) {
        out.print(x);
        out.flush();
    }

   /**
     * Prints a formatted string to standard output, using the specified format
     * string and arguments, and then flushes standard output.
     *
     * @param format the format string
     * @param args   the arguments accompanying the format string
     */
    public static void printf(String format, Object... args) {
        out.printf(LOCALE, format, args);
        out.flush();
    }

   /**
     * Prints a formatted string to standard output, using the locale and
     * the specified format string and arguments; then flushes standard output.
     *
     * @param locale the locale
     * @param format the format string
     * @param args   the arguments accompanying the format string
     */
    public static void printf(Locale locale, String format, Object... args) {
        out.printf(locale, format, args);
        out.flush();
    }

   /**
     * Simple unit test for <tt>StdOut</tt>.
     */
    public static void main(String[] args) {

        // write to stdout
        StdOut.println("Test");
        StdOut.println(17);
        StdOut.println(true);
        StdOut.printf("%.6f\n", 1.0/7.0);
    }

}


Copyright © 2000–2011, Robert Sedgewick and Kevin Wayne.
Last updated: Wed Sep 2 06:45:01 EDT 2015.