//********************************************************************
//  Countdown.java       Author: Lewis and Loftus
//
//  Demonstrates the difference between print and println.
//********************************************************************

public class Countdown
{
   //-----------------------------------------------------------------
   //  Prints two lines of output representing a rocket countdown.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      System.out.print ("Three... ");
      System.out.print ("Two... ");
      System.out.print ("One... ");
      System.out.print ("Zero... ");

      System.out.println ("Liftoff!"); // appears on first output line

      System.out.println ("Houston, we have a problem.");
   }
}


//********************************************************************
//  Facts.java       Author: Lewis and Loftus
//
//  Demonstrates the use of the string concatenation operator and the
//  automatic conversion of an integer to a string.
//********************************************************************

public class Facts
{
   //-----------------------------------------------------------------
   //  Prints various facts.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      // Strings can be concatenated into one long string
      System.out.println ("We present the following facts for your "
                          + "extracurricular edification:");

      System.out.println ();

      // A string can contain numeric digits
      System.out.println ("Letters in the Hawaiian alphabet: 12");

      // A numeric value can be concatenated to a string
      System.out.println ("International dialing code for Antarctica: "
                          + 672);

      System.out.println ("Year in which Leonardo da Vinci invented "
                          + "the parachute: " + 1515);

      System.out.println ("Speed of ketchup: " + 40 + " km per year");
   }
}


//********************************************************************
//  Addition.java       Author: Lewis and Loftus
//
//  Demonstrates the difference between the addition and string
//  concatenation operators.
//********************************************************************

public class Addition
{
   //-----------------------------------------------------------------
   //  Concatenates and adds two numbers and prints the results.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      System.out.println ("24 and 45 concatenated: " + 24 + 45);

      System.out.println ("24 and 45 added: " + (24 + 45));
   }
}



//********************************************************************
//  Poem.java
//
//  Demonstrates the use of escape sequences.
//********************************************************************

public class Poem
{
   //-----------------------------------------------------------------
   //  Prints a poem (by Emily Dickinson) on multiple lines.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      System.out.println ("In this short Life\n\tThat only lasts an hour\n" +
         "How much -- how little -- is\n\tWithin our power");
   }
}


//********************************************************************
//  StringMutation.java       
//
//  Demonstrates the use of the String class and its methods.
//********************************************************************

public class StringMutation
{
   //-----------------------------------------------------------------
   //  Prints a string and various mutations of it.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      String phrase = new String ("If you are not living life on the edge");
      String mutation1, mutation2, mutation3, mutation4;

      System.out.println ("Original string: \"" + phrase + "\"");
      System.out.println ("Length of string: " + phrase.length());

      mutation1 = phrase.concat (", you are taking up too much space.");
      mutation2 = mutation1.toUpperCase();
      mutation3 = mutation2.replace ('E', 'X');
      mutation4 = mutation3.substring (2, 12);

      // Print each mutated string
      System.out.println ("Mutation #1: " + mutation1);
      System.out.println ("Mutation #2: " + mutation2);
      System.out.println ("Mutation #3: " + mutation3);
      System.out.println ("Mutation #4: " + mutation4);

      System.out.println ("Mutated length: " + mutation4.length());
   }
}




//********************************************************************
//  RandomNumbers.java       Author: Lewis and Loftus
//
//  Demonstrates the import statement, and the creation of pseudo-
//  random numbers using the Random class.
//********************************************************************

import java.util.Random;

public class RandomNumbers
{
   //-----------------------------------------------------------------
   //  Generates random numbers in various ranges.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      Random generator = new Random();
      int num1;
      float num2;

      num1 = generator.nextInt();
      System.out.println ("A random integer: " + num1);

      num1 = Math.abs (generator.nextInt()) % 10;
      System.out.println ("0 to 9: " + num1);

      num1 = Math.abs (generator.nextInt()) % 10 + 1;
      System.out.println ("1 to 10: " + num1);

      num1 = Math.abs (generator.nextInt()) % 20 + 10;
      System.out.println ("10 to 29: " + num1);

      num2 = generator.nextFloat();
      System.out.println ("A random float [between 0-1]: " + num2);

      num2 = generator.nextFloat() * 6;  // 0.0 to 5.999999
      num1 = (int) num2 + 1;
      System.out.println ("1 to 6: " + num1);
   }
}



//********************************************************************
//  Echo.java
//
//  Demonstrates the use of the Scanner class
//********************************************************************

import java.util.Scanner;

public class Echo
{
   //-----------------------------------------------------------------
   //  Reads a character string from the user and prints it.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
	String message;
	Scanner scan = new Scanner(System.in);

	System.out.println ("Enter a line of text:");

	message = scan.nextLine(); 

	System.out.println ("You entered: \"" + message + "\"");
   }
}



//********************************************************************
//  PriceOfHappiness.java       
//
//  Demonstrates the use of various Scanner and NumberFormat
//  methods.
//********************************************************************

import java.util.Scanner;
import java.text.NumberFormat;

public class PriceOfHappiness
{
   //-----------------------------------------------------------------
   //  Calculates the final price of a purchased item using values
   //  entered by the user.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      final double TAX_RATE = 0.14;  // 14% sales tax

      int quantity;
      double subtotal, tax, totalCost, unitPrice;
      Scanner scan = new Scanner(System.in);

      System.out.print ("Enter the quantity of chocolate bars you want: ");
      quantity = scan.nextInt();

      System.out.print ("Enter the unit price: ");
      unitPrice = scan.nextDouble();

      subtotal = quantity * unitPrice;
      tax = subtotal * TAX_RATE;
      totalCost = subtotal + tax;

      // Print output with appropriate formatting
      NumberFormat money = NumberFormat.getCurrencyInstance();
      NumberFormat percent = NumberFormat.getPercentInstance();

      System.out.println ("Subtotal: " + money.format(subtotal));
      System.out.println ("Tax: " + money.format(tax) + " at "
                          + percent.format(TAX_RATE));
      System.out.println ("Total price for satisfying your craving: " + money.format(totalCost));
   }
}



//********************************************************************
//  CircleStats.java
//
//  Demonstrates the formatting of decimal values using the
//  DecimalFormat class.
//********************************************************************

import java.util.Scanner;
import java.text.DecimalFormat;

public class CircleStats
{
   //-----------------------------------------------------------------
   //  Calculates the area and circumference of a circle given its
   //  radius.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      int radius;
      double area, circumference;

      Scanner scan = new Scanner(System.in);

      System.out.print ("Enter the circle's radius: ");
      radius = scan.nextInt();

      area = Math.PI * Math.pow(radius, 2);
      circumference = 2 * Math.PI * radius;

      // Round the output to three decimal places
      DecimalFormat fmt = new DecimalFormat ("0.###");

      System.out.println ("The circle's area: " + fmt.format(area));
      System.out.println ("The circle's circumference: "
                          + fmt.format(circumference));
   }
}