constexpr complex(const T& re = T(), const T& im = T());
template<class X> constexpr explicit(see below) complex(const complex<X>& other);
constexpr T real() const;
constexpr void real(T val);
constexpr T imag() const;
constexpr void imag(T val);
constexpr complex& operator+=(const T& rhs);
constexpr complex& operator-=(const T& rhs);
constexpr complex& operator*=(const T& rhs);
constexpr complex& operator/=(const T& rhs);
template<class X> constexpr complex& operator+=(const complex<X>& rhs);
template<class X> constexpr complex& operator-=(const complex<X>& rhs);
template<class X> constexpr complex& operator*=(const complex<X>& rhs);
template<class X> constexpr complex& operator/=(const complex<X>& rhs);
template<class T> constexpr complex<T> operator+(const complex<T>& lhs);
template<class T> constexpr complex<T> operator+(const complex<T>& lhs, const complex<T>& rhs);
template<class T> constexpr complex<T> operator+(const complex<T>& lhs, const T& rhs);
template<class T> constexpr complex<T> operator+(const T& lhs, const complex<T>& rhs);
template<class T> constexpr complex<T> operator-(const complex<T>& lhs);
template<class T> constexpr complex<T> operator-(const complex<T>& lhs, const complex<T>& rhs);
template<class T> constexpr complex<T> operator-(const complex<T>& lhs, const T& rhs);
template<class T> constexpr complex<T> operator-(const T& lhs, const complex<T>& rhs);
template<class T> constexpr complex<T> operator*(const complex<T>& lhs, const complex<T>& rhs);
template<class T> constexpr complex<T> operator*(const complex<T>& lhs, const T& rhs);
template<class T> constexpr complex<T> operator*(const T& lhs, const complex<T>& rhs);
template<class T> constexpr complex<T> operator/(const complex<T>& lhs, const complex<T>& rhs);
template<class T> constexpr complex<T> operator/(const complex<T>& lhs, const T& rhs);
template<class T> constexpr complex<T> operator/(const T& lhs, const complex<T>& rhs);
template<class T> constexpr bool operator==(const complex<T>& lhs, const complex<T>& rhs);
template<class T> constexpr bool operator==(const complex<T>& lhs, const T& rhs);
template<class T, class charT, class traits>
basic_istream<charT, traits>& operator>>(basic_istream<charT, traits>& is, complex<T>& x);
template<class T, class charT, class traits>
basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& o, const complex<T>& x);
template<class T> constexpr T real(const complex<T>& x);
template<class T> constexpr T imag(const complex<T>& x);
template<class T> T abs(const complex<T>& x);
template<class T> T arg(const complex<T>& x);
template<class T> constexpr T norm(const complex<T>& x);
template<class T> constexpr complex<T> conj(const complex<T>& x);
template<class T> complex<T> proj(const complex<T>& x);
template<class T> complex<T> polar(const T& rho, const T& theta = T());
template<class T> complex<T> acos(const complex<T>& x);
template<class T> complex<T> asin(const complex<T>& x);
template<class T> complex<T> atan(const complex<T>& x);
template<class T> complex<T> acosh(const complex<T>& x);
template<class T> complex<T> asinh(const complex<T>& x);
template<class T> complex<T> atanh(const complex<T>& x);
template<class T> complex<T> cos(const complex<T>& x);
template<class T> complex<T> cosh(const complex<T>& x);
template<class T> complex<T> exp(const complex<T>& x);
template<class T> complex<T> log(const complex<T>& x);
template<class T> complex<T> log10(const complex<T>& x);
template<class T> complex<T> pow(const complex<T>& x, const complex<T>& y);
template<class T> complex<T> pow(const complex<T>& x, const T& y);
template<class T> complex<T> pow(const T& x, const complex<T>& y);
template<class T> complex<T> sin(const complex<T>& x);
template<class T> complex<T> sinh(const complex<T>& x);
template<class T> complex<T> sqrt(const complex<T>& x);
template<class T> complex<T> tan(const complex<T>& x);
template<class T> complex<T> tanh(const complex<T>& x);
constexpr complex<long double> operator""il(long double d);
constexpr complex<long double> operator""il(unsigned long long d);
constexpr complex<double> operator""i(long double d);
constexpr complex<double> operator""i(unsigned long long d);
constexpr complex<float> operator""if(long double d);
constexpr complex<float> operator""if(unsigned long long d);