/****************************************************************************** * 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; /** * The {@code StdOut} class provides static methods for printing strings * and numbers to standard output. * *

Getting started. * To use this class, you must have {@code StdOut.class} in your * Java classpath. If you used our autoinstaller, you should be all set. * Otherwise, either download * stdlib.jar * and add to your Java classpath or download * StdOut.java * and put a copy in your working directory. *

* Here is an example program that uses {@code StdOut}: *

 *   public class TestStdOut {
 *       public static void main(String[] args) {
 *           int a = 17;
 *           int b = 23;
 *           int sum = a + b;
 *           StdOut.println("Hello, World");
 *           StdOut.printf("%d + %d = %d\n", a, b, sum);
 *       }
 *   }
 *  
*

* Differences with System.out. * The behavior of {@code StdOut} is similar to that of {@link System#out}, * but there are a few technical differences: *

*

* Reference. * For additional documentation, * see Section 1.5 of * Computer Science: An Interdisciplinary Approach * 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() { } /** * 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. *

* 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(); } /** * Unit tests some methods in {@code StdOut}. * * @param args the command-line arguments */ 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); } }