/** @file list2704.cpp */
/** Listing 27-4. Adding the assign Member Function */
#include <cassert>
#include <cstdlib>
#include <iostream>
#include <ostream>

/// Compute the greatest common divisor of two integers, using Euclid’s algorithm.
int gcd(int n, int m)
{
  n = abs(n);
  while (m != 0) {
    int tmp(n % m);
    n = m;
    m = tmp;
  }
  return n;
}

/// Represent a rational number.
struct rational
{
  /// Assign a numerator and a denominator, then reduce to normal form.
  /// @param num numerator
  /// @param den denominator
  /// @pre denominator > 0
  void assign(int num, int den)
  {
    numerator = num;
    denominator = den;
    reduce();
  }

  /// Reduce the numerator and denominator by their GCD.
  void reduce()
  {
    assert(denominator != 0);
    int div(gcd(numerator, denominator));
    numerator = numerator / div;
    denominator = denominator / div;
  }

  int numerator;     ///< numerator gets the sign of the rational value
  int denominator;   ///< denominator is always positive
};

int main()
{
  rational pi;
  pi.assign(1420, 452);
  std::cout << "pi is about " << pi.numerator << "/" << pi.denominator << '\n';
}