BellSound.java

/**
 * Make a bell sound in the terminal!
 */
public class BellSound {
  public static void main(String[] args) throws InterruptedException {
    System.out.println("Make a bell sound (🔔 turn your volume up!) by sending the ASCII code identified by the number 7 to the terminal");

    {
      System.out.println("Once!");
      System.out.write(7);
      System.out.flush();
      Thread.sleep(800);
    }

    {
      // This is the same thing. Binary is rarely used in Java source code, but if you are doing something low-level like
      // toying with ASCII and using a visual aid like this ASCII table (https://en.wikipedia.org/wiki/ASCII#/media/File:USASCII_code_chart.png)
      // which has binary values on the X and Y axes, then it can be educational to use binary.
      System.out.println("Twice!");
      System.out.write(0b00000111);
      System.out.flush();
      Thread.sleep(800);
    }

    {
      // This is the same thing. Hexadecimal values are often used in source code to express terminal control
      // characters.
      System.out.println("Thrice!");
      System.out.write(0x7);
      System.out.flush();
      Thread.sleep(800);
    }

    {
      // This is the same thing. Unicode values are often used in source code to express terminal control
      // characters.
      System.out.println("A fourth time!");
      System.out.write('\u0007');
      System.out.flush();
      Thread.sleep(800);
    }

    {
      // This is the same thing. Unicode characters can be conveniently expressed in string constants in Java code.
      System.out.println("\u0007A fifth time!");
      System.out.flush();
      Thread.sleep(800);
    }

    {
      // This is the same thing. Octal numbers can be conveniently expressed in string constants in Java code.
      System.out.println("\007A sixth and final bell!");
    }

    System.out.println("This code is known as a 'control character', as are all codes in the decimal range 0-31. Read more about control characters on Wikipedia: https://en.wikipedia.org/wiki/ASCII#Control_characters");
  }
}