The ADT of the class Fraction is:
	Members:

   private int numerator;
   private int denominator;	//must be > 0

This implements the interface of Comparable

	Methods:

PUBLIC methods:

Constructor:
PRECONDITIONS:  none
INPUT:		none
PROCESS:	It creates the the Fraction and assigns numerator to be
		to be 0 and the denominator to be 1.
OUTPUT:		none
POSTCONDITIONS: The Fraction is created.

Constructor:
PRECONDITIONS:  none
INPUT:		int numer 
PROCESS:	It creates the the Fraction and assigns numerator to be
		num and denominator to be 1. 
OUTPUT:		none
POSTCONDITIONS: The Fraction is created.

Constructor:
PRECONDITIONS:  denom is not zero
INPUT:		int numer, int denom
PROCESS:	It creates the the Fraction and assigns numerator to be
		num and denominator to be denom.  It makes sure that denom is
		positive, and if not, modifies it to be so.  It reduces the
		values so that the least common denominator of the fraction is
		one.
OUTPUT:		none
POSTCONDITIONS: The Fraction is created.

add
PRECONDITIONS:  none
INPUT:		Fraction to be added
PROCESS:	It creates a new Fraction which is the sum of the two
		Fractions.
OUTPUT:		new Fraction which is the sum of the two.
POSTCONITIONS:	none

subtract
PRECONDITIONS:  none
INPUT:		Fraction to be subtracted
PROCESS:	It creates a new Fraction which is the difference of the
		two Fractions.
OUTPUT:		new Fraction which is the difference of the two.
POSTCONITIONS:	none

multiply
PRECONDITIONS:  none
INPUT:		Fraction to be multiplied
PROCESS:	It creates a new Fraction which is the product of the two
		Fractions.
OUTPUT:		new Fraction which is the product of the two.
POSTCONITIONS:	none

divide
PRECONDITIONS:  The input Fraction must not be zero.
INPUT:		Fraction to be divided
PROCESS:	It creates a new Fraction which is the quotient of the
		two Fractions.
OUTPUT:		new Fraction which is the quotient of the two.
POSTCONITIONS:	none

reciprocal
PRECONDITIONS:  The Fraction itself must not have numerator zero.
INPUT:		none
PROCESS:	It creates a new Fraction which is the reciprocal of the
		Fraction.
OUTPUT:		new Fraction which is the reciprocal of the original.
POSTCONDITIONS:	none 

increment
PRECONDITIONS:  none
INPUT:		none
PROCESS:	It adds one to the Fraction.
OUTPUT:		none
POSTCONDITIONS:	It increments the value of the Fraction by one

getNumerator
PRECONDITIONS:  none
INPUT:		none
PROCESS:	It returns the numerator.
OUTPUT:		the numerator (an integer)
POSTCONDITIONS:	none

getDenominator
PRECONDITIONS:  none
INPUT:		none
PROCESS:	It returns the denominator.
OUTPUT:		the denominator (an integer)
POSTCONDITIONS:	none

equals
PRECONDITIONS:  none
INPUT:		The Fraction to which one compares
PROCESS:	It returns true if the Fractions are equal, otherwise
		false.
OUTPUT:		boolean, true if the two Fractions are equal
POSTCONDITIONS:	none

assigns
PRECONDITIONS:  none
INPUT:		The Fraction to which one assigns the value
PROCESS:	It assigns the values of the input Fraction to the Fraction.
		No new Fraction is created.
OUTPUT:		none
POSTCONDITIONS:	The fraction has changed its value

compareTo
PRECONDITIONS:  none
INPUT:		The Fraction to which one compares
PROCESS:	It returns a positive number if the Fraction sent is less
		than the Fraction, zero if they are equal, and a 
		negative number if the Fraction sent is larger than the
		Fraction.
OUTPUT:		int, positive if larger than one to compare to, zero if equal,
		and negative if smaller than the one sent to compare to.
POSTCONDITIONS:	none

toString
PRECONDITIONS:  none
INPUT:		none
PROCESS:	It returns a string which is to be used in the System.out
		to generate output.
OUTPUT:		A String which is the output of printing the Fraction.
POSTCONDITIONS:	none

PRIVATE methods

reduce
PRECONDITIONS:  none
INPUT:		none
PROCESS:	It divides the numerator and denominator by their greatest
		common divisor.
OUTPUT:		none
POSTCONDITIONS:	numerator and denominator are modified

gcd
PRECONDITIONS:  none
INPUT:		two integers
PROCESS:	It finds the great common divisor of the two integers.
OUTPUT:		an integer, their greatest common divisor
POSTCONDITIONS:	none