#include <iostream.h>
#include "frac.h"
/*
int main()
{
  frac a, b, c;

  a.set(3,5);
  b.set(-4,5);

  cout << b.sign << ' ' << b.upper << '/' << b.lower << endl;

  c = a * b;
  cout << c.sign << ' ' << c.upper << "/" << c.lower << endl;

  c = a / b;
  cout << c.sign << ' ' << c.upper << "/" << c.lower << endl;

  a.set(-3, 2);
  b.set(1, 3);

  c = a * b;
  cout << c.sign << ' ' << c.upper << "/" << c.lower << endl;

  a.set(-1, 2);
  b.set(1, 3);

  c = a * b;
  cout << c.sign << ' ' << c.upper << "/" << c.lower << endl;

  return 0;
}
*/
unsigned int frac::gcd(unsigned int a, unsigned int b)
{
  if (a == 0) {
    return b;
  }
  if (b == 0) {
    return a;
  }
  if (a < b) {
    return gcd(a, b%a);
  }
  else {
    return gcd(b, a%b);
  }
}

void frac::set(int u, unsigned int l)
{
  if (u < 0) {
    sign = 1;
    upper = -u;
  }
  else {
    sign = 0;
    upper = u;
  }
  lower = l;

  return;
}

frac::frac(int i)
{
  if (i < 0) {
    sign = 1;
    upper = -i;
  }
  else {
    sign = 0;
    upper = i;
  }
  lower = 1;
}

frac::frac(int u, unsigned int l)
{
  if (u < 0) {
    sign = 1;
    upper = -u;
  }
  else {
    sign = 0;
    upper = u;
  }
  lower = l;
}

frac frac::operator + (frac src)
{
  frac ans;
  int buf;

  ans.lower = lower * src.lower;
  ans.upper = upper * src.lower;
  ans.sign = sign;

  src.lower *= lower;
  src.upper *= lower;

  switch (ans.sign) {
  case 0:
    switch (src.sign) {
    case 0:  //  ans->'+', src->'+'
      ans.upper += src.upper;
      ans.sign = 0;
      break;
    default:  //  ans->'+', src->'-'
      if (ans.upper < src.upper) {
        ans.sign = 1;
        ans.upper = src.upper - ans.upper;
      }
      else {
        ans.sign = 0;
        ans.upper -= src.upper;
      }
    }
    break;
  default:
    switch (src.sign) {
    case 0:  //  upper->'-', lower->'+'
      if (ans.upper < src.upper) {
        ans.sign = 0;
        ans.upper = src.upper - ans.upper;
      }
      else {
        ans.sign = 1;
        ans.upper -= src.upper;
      }
      break;
    default:  //  upper->'-', lower->'-'
      ans.upper += src.upper;
      ans.sign = 1;
      break;
    }
  }

  simplize(&ans);

  return ans;
}

frac frac::operator - (frac src) {
  src.sign = !src.sign;

  return *this + src;
}

frac frac::operator * (frac src) {
  frac ans;

  ans.upper = upper * src.upper;
  ans.lower = lower * src.lower;

  if (sign == 0) {
    if (src.sign == 0) {
      ans.sign = 0;
    }
    else {
      ans.sign = 1;
    }
  }
  else {
    if (src.sign == 0) {
      ans.sign = 1;
    }
    else {
      ans.sign = 0;
    }
  }

  simplize(&ans);

  return ans;
}

frac frac::operator / (frac src)
{
  frac buf;

  buf.sign = src.sign;
  buf.upper = src.lower;
  buf.lower = src.upper;

  return *this * buf;
}

void frac::simplize(frac *f)
{
  unsigned int buf;

  if (f->upper == 0) {
    f->lower = 1;
    f->sign = 0;
  }
  else {
    buf = gcd(f->upper, f->lower);
    f->lower /= buf;
    f->upper /= buf;
  }

  return;
}