/*
 * Rational: A class that implements a rational number as
 * a fraction.
 */

public class Rational {
	/* instance variables */
	private int numer;		// numerator
	private int denom;		// denominator

	/* private utility method for setting data */
	private void set( int n, int d ) { numer = n; denom = d; }

	/* no-argument (default) Constructor */
	public Rational( ) { set( 0, 1 ); }
	
	/* basic Constructor */
	public Rational( int n, int d ) { set( n, d ); }

	/* construct from int */
	public Rational( int n ) { set( n, 1 ); }
	
	/* copy Constructor */
	public Rational( Rational r ) {
		if ( r == null ) {				// cannot initialize from null!
			System.out.println( "Illegal construction from null reference" );
			System.exit( 0 );
		}
		set( r.numer, r.denom );
	}

	/* convert to string */
	public String toString( ) {
		String result = numer + "/" + denom + " ( " + doubleValue( ) + " )";
		return result;
	}
	
	/* accessors */
	public int getNumerator( )   { return numer; }
	public int getDenominator( ) { return denom; }
	public double doubleValue( ) { return ( double ) numer  / ( double) denom; }
	public float floatValue( )  { return ( float ) numer  / ( float ) denom; }

	/* mutators */
	public void setNumerator( int n ) { numer = n; }
	public void setDenominator( int d ) { denom = d; }
	public void setValue( int v ) { set( v, 1 ); }

	/* equality comparison */
	public static boolean equals( Rational q, Rational r )
		{ return q.numer * r.denom == r.numer * q.denom; }

	public boolean equals( Rational r )
		{ return equals ( this, r ); }

	public static boolean identical( Rational q, Rational r )
		{ return q.numer == r.numer && q.denom == r.denom; }

	/* reciprocal */
	public static Rational reciprocal( Rational r )
		{ return new Rational( r.denom, r.numer ); }

	public void reciprocal( ) 
		{ set( denom, numer ); }

	/* multiplication (static and mutator) */
	public static Rational multiply( Rational q, Rational r )
		{ return new Rational( q.numer * r.numer, q.denom *r.denom ); }

	public void multiplyBy( Rational r )
		{  numer *= r.numer;  denom *= r.denom;  }
}