#include <iostream>

using namespace std;

class Fraction {
public:
    int numer;
    int denom;

public:
    Fraction();
    Fraction( int numer , int denom );
    int getGCD();

    Fraction operator + ( Fraction & f  );
    bool operator < ( Fraction & f );
    operator double()	{	return double(numer) / double(denom);	}
};

ostream& operator << (  ostream & out,  Fraction & f  );

Fraction::Fraction(int numer , int denom)
{
    if (denom == 0)
        throw 0;

    int gcd = getGCD();
    if (gcd > 1) {
       numer /= gcd;
       denom /= gcd;
    }

}

int Fraction::getGCD()
{
    int n =  ( numer < denom ) ?  numer : denom ;
    int n1, n2;
    for (  ; n>=1 ; n-- ) {
        n1 = numer % n ;
        n2 = denom % n ;
        if ( n1==0  && n2==0 ) {
            break;
        }
    }
    return n;
}

int main()
{
    try {
        Fraction f( 3, 0 );
        double d = double(f);
    }
    catch ( int err ) {
        cout << "divide by " << err << endl;
    }

    return 0;
}