fraction.java

Create a problem solver for linear programming

/*
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 */

package ro.utils;

/**
 *
 * @author Doan Chien Thang
 */
public class Fraction {
    private int numerator;
    private int denominator;

    public Fraction(int n, int d) {
        try {
            if (d == 0)
                throw new Exception("Division by zero");
            n = (d > 0) ? n : -n;
            d = (d > 0) ? d : -d;
            this.numerator = n;
            this.denominator = d;
        } catch (Exception e) {
            System.err.println(e.getMessage());
        }
    }

    public Fraction(int n) {
        this(n, 1);
    }

    public Fraction (Fraction f) {
        this.numerator = f.numerator;
        this.denominator = f.denominator;
    }

    public static Fraction add(Fraction f, Fraction g) {
        int numerator = f.denominator * g.numerator +
                f.numerator * g.denominator;
        int denominator = f.denominator * g.denominator;
        return new Fraction(numerator, denominator).irreductibleForm();
    }

    public static Fraction substract(Fraction f, Fraction g) {
        int numerator = f.numerator * g.denominator - 
                f.denominator * g.numerator;
        int denominator = f.denominator * g.denominator;
        return new Fraction(numerator, denominator).irreductibleForm();
    }

    public static Fraction multiple(Fraction f, Fraction g) {
        return new Fraction(f.numerator * g.numerator,
                f.denominator * g.denominator).irreductibleForm();
    }

    public static Fraction divide(Fraction f, Fraction g) {
        return new Fraction(f.numerator * g.denominator,
                f.denominator * g.numerator).irreductibleForm();
    }

    public Fraction absolute() {
        if (this.numerator < 0)
            return new Fraction(-this.numerator, this.denominator).irreductibleForm();
        else
            return this;
    }

    public Fraction getOpposite() {
        return new Fraction(-this.numerator, this.denominator).irreductibleForm();
    }

    public boolean isGreaterThan(Fraction f) {
        return (this.numerator * f.denominator >=
                this.denominator * f.numerator);
    }

    public boolean isNegative() {
        return this.numerator < 0;
    }

    public boolean equals(Fraction f) {
        return (this.numerator * f.denominator ==
                this.denominator * f.numerator);
    }

    public boolean equals(int i) {
        return equals(new Fraction(i, 1));
    }

    public Fraction irreductibleForm() {
        if (this.numerator == 0)
            return new Fraction(0);
        int n = this.numerator > 0 ? this.numerator : -this.numerator;
        int d = this.denominator;
        int m;
        while (d > 0) {
            m = n % d;
            n = d;
            d = m;
        }
        if (n != 0)
            return new Fraction(this.numerator/n, this.denominator/n);
        else
            return new Fraction(0);
    }

    @Override
    public String toString() {
        if (this.numerator % this.denominator == 0)
            return new Integer(this.numerator / this.denominator).toString();
        else
            return (this.numerator + "/" + this.denominator);
    }

    public static void main(String[] args) {
        Fraction f = new Fraction(120, 36);
        System.out.println(f.irreductibleForm());
    }
}