// FractionDemo.java
// Developed in class on 29-July-2008

import java.util.*;

public class FractionDemo {
  public static Scanner scanner = new Scanner(System.in);

  public static void testFraction() {
    System.out.println("Testing Fraction class...");
    Fraction f1 = new Fraction(3,4); // 3/4;
    Fraction f2 = new Fraction(2,3); // 2/3;
    Fraction f3 = f1.add(f2); // f1 + f2; // 17/12
    // System.out.println(f1 + " + " + f2 + " = " + f3);
    assert(f3.equals(new Fraction(17,12)));
    assert(f3.toString().equals("17/12"));

    f3 = f1.add(f1); // 3/4 + 3/4 = 6/4 = 3/2
    // System.out.println(f1 + " + " + f1 + " = " + f3);
    assert(f3.equals(new Fraction(3,2)));
    assert(f3.toString().equals("3/2"));

    f1 = new Fraction(1,2);
    f2 = new Fraction(-1,-2);
    // assert(f1.equals(f2));  // this will FAIL!!!
    System.out.println("PASSED ALL TESTS!");
  }

  public static void main(String[] args) {
    testFraction();
  }
}


class Fraction {
  private int num, den; // numerator and denominator

  // helper methods
  private int gcd(int i1, int i2) {
    i1 = Math.abs(i1); // if (i1 < 0) i1 = -i1;
    i2 = Math.abs(i2); // if (i2 < 0) i2 = -i2;
    // @TODO: use Euler's method; it's faster
    for (int i=Math.min(i1,i2); i>1; i--)
      if (((i1 % i) == 0) && ((i2 % i) == 0))
        return i;
    return 1;
  }

  // constructor
  public Fraction(int num, int den) {
    int gcd = gcd(num, den);
    this.num = num/gcd;
    this.den = den/gcd;
  }

  // equals
  public boolean equals(Fraction that) {
    return ((this.num == that.num) && (this.den == that.den));
  }

  // toString
  public String toString() {
    return this.num + "/" + this.den;
  }

  // arithmetic methods
  public Fraction add(Fraction that) {
    // a/b  + c/d = (ad + bc) / bd
    int num = (this.num*that.den) + (this.den*that.num);
    int den = this.den*that.den;
    return new Fraction(num, den);
  }
}