EquationRoots CEquationSolver::GetEquationRoots() const
{
const auto epsilon = std::numeric_limits<double>::epsilon();
if (std::abs(m_a) > epsilon)
{
double discr = m_b * m_b - 4 * m_a * m_c;
if (discr < 0)
{
return NoRealRoots();
}
else if (discr < std::numeric_limits<double>::epsilon())
{
return (-m_b + std::sqrt(discr)) / (2 * m_a);
}
else
{
return std::make_pair((-m_b - std::sqrt(discr)) / (2 * m_a),
(-m_b + std::sqrt(discr)) / (2 * m_a));
}
}
// linear equation b*x + c = 0
if (std::abs(m_b) >= epsilon)
{
return -m_c / m_b;
}
else if (std::abs(m_c) >= epsilon)
{
return NoRealRoots();
}
else // 0*x = 0
{
return InfiniteNumberOfRoots();
}
}
QuadraticEquationSolution ComputeRoots(const double & a, const double & b, const double & c)
{
if (a == 0)
{
return NotAQuadraticEquation();
}
const double discriminant = ComputeDiscriminant(a, b, c);
if (discriminant < 0)
{
return NoRealRoots();
}
if (discriminant == 0)
{
return -b / 2 * a; // one root
}
return std::make_pair((-b + sqrt(discriminant)) / (2 * a),
(-b - sqrt(discriminant)) / (2 * a)); // Two roots
}
