std::complex::complex(3)

NAME
std::complex::complex - std::complex::complex

Synopsis
Primary template (std::complex<T>) complex( const T& re (until = T(), const T& im = C++14) T() ); constexpr complex( (since const T& re = T(), C++14) const T& im = T() ); complex( const (until complex& other ); C++14) constexpr complex( (since const complex& other C++14) ); (until
                        C++23) constexpr complex( (since const complex& other C++23) ) = default; template< class X > (until complex( const C++14) complex<X>& other ); template< class X > (since constexpr complex( C++14) const complex<X>& (until other ); C++23) template< class X > constexpr explicit(/* see (since below */) complex( C++23) const complex<X>& other ); Standard explicit specialization std::complex<float> (until C++23) complex( float re = (until 0.0f, float im = C++11) 0.0f ); constexpr complex( (since float re = 0.0f, C++11) float im = 0.0f ); constexpr complex( const (2) (since complex<float>& C++20) other ) = default; explicit complex( const complex<double>& (until other ); C++11) explicit complex( const complex<long double>& other ); constexpr explicit complex( const complex<double>& other ); (since constexpr explicit C++11) complex( const complex<long double>& other ); Standard explicit (1) specialization std::complex<double> (until C++23) (2) complex( double re = (until 0.0, double im = 0.0 C++11) ); constexpr complex( (3) (since double re = 0.0, C++11) double im = 0.0 ); constexpr complex( const (2) (since complex<double>& C++20) other ) = default; complex( const complex<float>& other ); (1) (until explicit complex( C++11) const complex<long double>& other ); constexpr complex( const (3) complex<float>& other ); (since constexpr explicit C++11) complex( const complex<long double>& other ); Standard explicit specialization std::complex<long (1) double> (until C++23) complex( long double (until re = 0.0L, long C++11) double im = 0.0L ); (3) constexpr complex( long double re = (since 0.0L, long double im C++11) = 0.0L ); constexpr complex( const complex<long (2) (since double>& other ) = C++20) default; complex( const complex<float>& (1) other ); (until complex( const C++11) complex<double>& other ); constexpr complex( (3) const complex<float>& other ); (since constexpr complex( C++11) const complex<double>& other );
   Constructs the std::complex object.
   The standard explicit specializations (std::complex<float>, std::complex<double> and
   std::complex<long double>) have different constructor declarations from the main
   template.
   (until C++23)
   1) Constructs the complex number from real part re and imaginary part im.
   2) Copy constructor. Constructs the object with the copy of the contents of other.
   The copy constructors are implicitly declared in the standard explicit
   specializations.
   (until C++20)
   3) Converting constructor. Constructs the object from a complex number of a
   different type.
   The main template provides a converting constructor template, while
   each standard explicit specialization provides two non-template
   constructors for the two other standard explicit specializations.
                        (until C++23)
   The non-template constructors are converting constructors (i.e.
   non-explicit) if and only if the conversions of the real and imaginary
   parts are not narrowing.
   For the main template, the expression inside explicit evaluates to
   false if and only if the floating-point conversion rank of T is (since C++23)
   greater than or equal to the floating-point conversion rank of X.

Parameters
   re - the real part
   im - the imaginary part
   other - another complex number to use as source

Notes
   Since C++23, the copy constructor is required to be trivial in order to satisfy the
   TriviallyCopyable requirement, but implementations generally make it trivial in all
   modes.

See also
   operator= assigns the contents
                (public member function)
   operator""if
   operator""i a std::complex literal representing purely imaginary number
   operator""il (function)
   (C++14)
   C documentation for
   CMPLX