// Sub sets z = x - y and returns z.
func (z *Int) Sub(x, y *Int) *Int {
	x.doinit()
	y.doinit()
	z.doinit()
	C.mpz_sub(&z.i[0], &x.i[0], &y.i[0])
	return z
}

// Mul sets z = x * y and returns z.
func (z *Int) Mul(x, y *Int) *Int {
	x.doinit()
	y.doinit()
	z.doinit()
	C.mpz_mul(&z.i[0], &x.i[0], &y.i[0])
	return z
}

// Div sets z = x / y, rounding toward zero, and returns z.