// Delegating ctors are different than in Java.
// Granted, this problem would be better solved by using default arguments.

#include <iostream>

class Ratio {
  public:
    Ratio(int a, int b) : numerator(a), denominator(b) {
	if (b==0)
	    throw "Can’t divide by zero!";
	// Should really reduce the fraction to lowest terms, here.
    }
    Ratio() {
	Ratio(1,1);			// Set default values 😈
    }
    double value() const { return numerator / (denominator+0.0); }
  private:
    int numerator, denominator;
    friend std::ostream & operator<<(std::ostream &, const Ratio &);
};

std::ostream & operator<<(std::ostream &out, const Ratio &r) {
    return out << r.numerator << '/' << r.denominator;
}

using namespace std;

int main() {
    Ratio r(012,345);
    cout << r << " = " << r.value() << '\n';

    Ratio q;					// Should be 1/1
    cout << q << " = " << q.value() << '\n';

    return 0;
}