#include <cstdio>
 
struct v3d
{
	double x, y, z;
};
 
struct v3d_mr // multiplication result
{
	double scalar;
	v3d vector;
 
	operator double () { return this->scalar; }
	operator v3d () { return this->vector; }
};
 
v3d_mr operator * (const v3d &a, const v3d &b)
{
	return
	{
		a.x*b.x + a.y*b.y + a.z*b.z,
		{ a.y*b.z - a.z*b.y, a.z*b.x - a.x*b.z, a.x*b.y - b.x*a.y }
	};
}
 
int main()
{
	v3d a = {1, 2, 3}, b = {4, 5, 6};
 
	double s = a * b;
	v3d v = a * b;
 
	printf("%lf\n", s);
	printf("%lf %lf %lf\n", v.x, v.y, v.z);
 
	return 0;
}

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