func (q *Rat) Sub(x, y *Rat) *Rat { x.doinit() y.doinit() q.doinit() C.mpq_sub(&q.i[0], &x.i[0], &y.i[0]) return q }
// Sub sets z to the difference x-y and returns z. func (z *Rat) Sub(x, y *Rat) *Rat { x.doinit() y.doinit() z.doinit() C.mpq_sub(&z.i[0], &x.i[0], &y.i[0]) return z }