com.marringtons.number
Class Fraction

java.lang.Object
  com.marringtons.number.Fraction

All Implemented Interfaces:

Comparable

public class Fraction

extends Object

implements Comparable

This is an immutable class representing fractions as 3 longs. Fractions are always maintained in reduced form. Fractions are truly magic things. 1/3 is way more accurate than 0.3333333333333. It is also easier to say and understand. Fractions multiply and divide way more quickly than floating point, but add more slowly (if denominators don't match). Have fun.

Author:

Paul Marrington

Field Summary

int	after Set by string constructor to the first non-space character after the number parsed.
long	denominator Denominator for the fractional number (the 3 in 1-2/3)
boolean	empty Set by string constructor if the string did not contain a fractional number.
long	numerator Numerator for the fractional number (the 2 in 2/3)

Constructor Summary

Fraction(long wholePart, long numerator, long denominator)
Constructor must fill final components of the fraction.

Fraction(String string)
Constructor to create fraction from a string.

Method Summary

int	compareTo(Object other)
Fraction	divide(Fraction by) Divide one fraction by another.
boolean	equals(Object other)
static long	greatestCommonDenominator(long numerator, long denominator)
int	hashCode()
Fraction	inverse() Invert the fraction (2/3 becomes 1-1/3).
Fraction	minus(Fraction less) Subtraction ine Fraction from another.
Fraction	negative() Negate a fraction
Fraction	plus(Fraction add) Add two fractions together.
Fraction	times(Fraction by) Multiply two fractions.
String	toHTML() String representation of a fractional number - making fractional part a superscript.
String	toString() String representation of a fractional number is 1, 1-1/3 or 2/5.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

numerator

public final long numerator

Numerator for the fractional number (the 2 in 2/3)

denominator

public final long denominator

Denominator for the fractional number (the 3 in 1-2/3)

empty

public final transient boolean empty

Set by string constructor if the string did not contain a fractional number.

 String myInput = "1 2/3";
 Fraction fraction = new Fraction( myInput);
 if (fraction.empty) Log( "Please enter a valid fraction");
 

after

public final transient int after

Set by string constructor to the first non-space character after the number parsed.

 String myInput = "1 2/3 abc";
 Fraction fraction = new Fraction( myInput);
 check( myInput.substring( fraction.after).equals( "abc");
 

Constructor Detail

Fraction

public Fraction(long wholePart,
                long numerator,
                long denominator)

Constructor must fill final components of the fraction.

Parameters:

wholePart - The 1 in 1-2/3

numerator - The 2 in 1-2/3

denominator - The 3 in 1-2/3

Fraction

public Fraction(String string)

Constructor to create fraction from a string. The string can be a fraction with or without a whole part or a decimal. If the string

Parameters:

string -

Method Detail

greatestCommonDenominator

public static long greatestCommonDenominator(long numerator,
                                             long denominator)

Parameters:

numerator - Top part of the fraction

denominator - Lower part of the fraction

Returns:

greatest common denominator - to reduce fraction to it's best value.

toString

public String toString()

String representation of a fractional number is 1, 1-1/3 or 2/5.

Returns:

String representation.

See Also:

Object.toString()

toHTML

public String toHTML()

String representation of a fractional number - making fractional part a superscript.

Returns:

HTML representation.

See Also:

Object.toString()

compareTo

public int compareTo(Object other)

Specified by:

compareTo in interface Comparable

See Also:

Comparable.compareTo(java.lang.Object)

negative

public Fraction negative()

Negate a fraction

Returns:

a fraction representing the negative of this one.

inverse

public Fraction inverse()

Invert the fraction (2/3 becomes 1-1/3).

Returns:

Inverse of fraction.

plus

public Fraction plus(Fraction add)

Add two fractions together.

Parameters:

add - Fraction to add.

Returns:

Normalised sum of both fractions.

minus

public Fraction minus(Fraction less)

Subtraction ine Fraction from another.

Parameters:

less - Fraction to subtract from this one.

Returns:

Normalised difference between both fractions.

times

public Fraction times(Fraction by)

Multiply two fractions.

Parameters:

by - Fraction to multiply by.

Returns:

Normalised multiplication of both fractions.

divide

public Fraction divide(Fraction by)

Divide one fraction by another.

Parameters:

by - Fraction to divide with.

Returns:

Normalised result of fractional division.

equals

public boolean equals(Object other)

See Also:

Object.equals(java.lang.Object)

hashCode

public int hashCode()

See Also:

Object.hashCode()