// Implementation of Fraction Class, watching out for integer overflows..
// Michael Rothstein
// 07/27/2014

// For many reasons, keep fractions in lowest terms
#include "Fraction.h"
#include <cstdlib>
#include <cassert>

Fraction::Fraction(long numerator,long denominator){
  /*  if ( denominator == 0 ) {
    cerr << "0 Denominators are not allowed!\n";
    exit(1);
    }*/
  assert(denominator != 0);
  if ( numerator == 0 ) denominator = 1;
  if ( denominator < 0 ) {
    numerator = -numerator;
    denominator = -denominator;
  }
  long g = gcd(numerator, denominator);
  numer = numerator/g;
  denom = denominator/g;
}

Fraction Fraction::operator+(const Fraction & a){
  long g = gcd(denom,a.denom);
  long c1 = denom/g;
  long c2 = a.denom/g;
  long newnum = numer*c2+a.numer*c1;
  long newdenom = denom * c2; // = a.denom * c1
  return Fraction(newnum,newdenom);
}

Fraction Fraction::operator-(const Fraction & a){
  long g = gcd(denom,a.denom);
  long c1 = denom/g;
  long c2 = a.denom/g;
  long newnum = numer*c2-a.numer*c1;
  long newdenom = denom * c2; // = a.denom * c1
  return Fraction(newnum,newdenom);
}

Fraction Fraction::operator*(const Fraction & a){
  long g1 = gcd(numer,a.denom);
  long g2 = gcd(denom,a.numer);
  return Fraction((numer/g1)*(a.numer/g2),(denom/g2)*(a.denom/g1));
}

Fraction Fraction::operator/(const Fraction & a){
  long g1 = gcd(numer,a.numer);
  long g2 = gcd(denom,a.denom);
  return Fraction((numer/g1)*(a.denom/g2),(denom/g2)*(a.numer/g1));
}

std::ostream& operator<<(std::ostream&os,const Fraction a){
  if ( a.denom == 1 ) os << a.numer;
  else os << a.numer << '/'<< a.denom;
  return os;
}