/** Currency class with private data member
  * amount of type long. */

package applications;

import java.text.*;   // has the NumberFormat and DecimalFormat classes

public class CurrencyAsLong
{
   // class constants
   public static final boolean PLUS = true;
   public static final boolean MINUS = false;
   public static final NumberFormat TWODIGIT = new DecimalFormat("00");

   // instance data member
   private long amount;

   // constructors
   /** initialize instance to
     * theSign $ theDollars.theCents
     * @throws IllegalArgumentException when theDollars < 0
     * or theCents < 0 or theCents > 99 */
   public CurrencyAsLong(boolean theSign, long theDollars,
                   byte theCents)
   {
      if (theDollars < 0)
         throw new IllegalArgumentException
               ("Dollar value must be >= 0");

      if (theCents < 0 || theCents > 99)
         throw new IllegalArgumentException
               ("Cents must be between 0 and 99");

      amount = theDollars * 100 + theCents;
      if (theSign == MINUS)
         amount = -amount;
   }

   /** initialize instance to $0.00 */
   public CurrencyAsLong()
      {this(PLUS, 0L, (byte) 0);}

   /** initialize with double */
   public CurrencyAsLong(double theValue)
      {setValue(theValue);}

   /** initialize with amount value */
   private CurrencyAsLong(long theAmount)
      {amount = theAmount;}

   // accessor methods

   /** @return sign */
   public boolean getSign()
   {
      if (amount < 0)
         return MINUS;
      else
         return PLUS;
   }

   /** @return dollars */
   public long getDollars()
   {
      if (amount < 0)
         return - amount / 100;
      else
         return amount / 100;
   }

   /** @return cents */
   public byte getCents()
   {
      if (amount < 0)
         return (byte) ((-amount) % 100);
      else
         return (byte) (amount % 100);
   }

   // mutator methods
   /** Set the sign of amount to theSign.
     * For this to work properly amount must be nonzero. */
   public void setSign(boolean theSign)
   {
      // change the sign as necessary
      if ((amount < 0 && theSign == PLUS) ||
          (amount > 0 && theSign == MINUS))
         amount = -amount;
   }
 
   /** set dollars = theDollars
     * @throws IllegalArgumentException when theDollars < 0 */
   public void setDollars(long theDollars)
   {
      if (theDollars < 0)
         throw new IllegalArgumentException
               ("Dollar value must be >= 0");
      else
      {
         boolean sign = getSign();
         byte cents = getCents();
         amount = theDollars * 100 + cents;
         if (sign == MINUS)
            amount = -amount;
      }
   }

   /** set cents = theCents
     * throws IllegalArgumentException when theCents < 0 or theCents > 99 */
   public void setCents(byte theCents)
   {
      if (theCents < 0 || theCents > 99)
         throw new IllegalArgumentException
               ("Cents must be between 0 and 99");
      else
      {
         boolean sign = getSign();
         long dollars = getDollars();
         amount = dollars * 100 + theCents;
         if (sign == MINUS)
            amount = -amount;
      }
   }

   /** set amount */
   public void setValue(double theValue)
   {
      if (theValue < 0)
         amount = (long) (theValue * 100 - 0.5);
      else
         amount = (long) (theValue * 100 + 0.5);
   }

   public void setValue(CurrencyAsLong x)
      {amount = x.amount;}
   
   /** convert to a string */
   public String toString()
   {
      if (amount >= 0)
         {return "$" + getDollars() + "." + TWODIGIT.format(getCents());}
      else
         {return "-$" + getDollars() + "." + TWODIGIT.format(getCents());}
   }

   // arithmetic methods

   /** @return this + x */
   public CurrencyAsLong add(CurrencyAsLong x)
      {return new CurrencyAsLong(amount + x.amount);}
   
   /** @return this incremented by x */
   public CurrencyAsLong increment(CurrencyAsLong x)
   {
      amount += x.amount;
      return this;
   }
   
   /** test program */
   public static void main(String [] args)
   {
      // test constructors
      CurrencyAsLong g = new CurrencyAsLong(),
                     h = new CurrencyAsLong(PLUS, 3L, (byte) 50),
                     i = new CurrencyAsLong(-2.50),
                     j = new CurrencyAsLong();

      // test toString
      System.out.println("The initial values are " + g +
                         " " + h + " " + i + " " + j);
      System.out.println();

      // test mutators
      // first make g nonzero
      g.setDollars(2);
      g.setSign(MINUS);
      g.setCents((byte) 25);
      i.setValue(-6.45);
      System.out.println("New values are " + g + " " + i);
      System.out.println();

      // do some arithmetic
      j = h.add(g);
      System.out.println(h + " + " + g + " = " + j);

      System.out.print(i + " incremented by " + h + " is ");
      i.increment(h);
      System.out.println(i);

      j = i.add(g).add(h);
      System.out.println(i + " + " + g + " + " + h +
                         " = " + j);
      System.out.println();

      j = i.increment(g).add(h);
      System.out.println(j);
      System.out.println(i);
   }
}