std::conj(std::complex)

 

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std::complex

Member functions
complex::complex complex::operator= complex::real complex::imag	complex::operator+=complex::operator-=complex::operator*=complex::operator/=
Non-member functions
operator+operator- operator+operator-operator*operator/ operator==operator!= (until C++20)   operator<<operator>> get(std::complex) (C++26)	real imag abs arg norm conj proj (C++11) polar operator""ioperator""ifoperator""il (C++14)(C++14)(C++14)
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sin   cos tan asin (C++11) acos (C++11) atan (C++11)
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sinh   cosh tanh asinh (C++11) acosh (C++11) atanh (C++11)
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tuple_size<std::complex> (C++26)
tuple_element<std::complex> (C++26)

 

Defined in header <complex>
	(1)
template< class T > std::complex<T> conj( const std::complex<T>& z );			(until C++20)
template< class T > constexpr std::complex<T> conj( const std::complex<T>& z );			(since C++20)
Additional overloads (since C++11)
Defined in header <complex>
		(A)
std::complex<float>       conj( float f ); std::complex<double>      conj( double f ); std::complex<long double> conj( long double f );				(until C++20)
constexpr std::complex<float>       conj( float f ); constexpr std::complex<double>      conj( double f ); constexpr std::complex<long double> conj( long double f );				(since C++20) (until C++23)
template< class FloatingPoint > constexpr std::complex<FloatingPoint> conj( FloatingPoint f );				(since C++23)
			(B)
template< class Integer > constexpr std::complex<double> conj( Integer i );					(until C++20)
template< class Integer > constexpr std::complex<double> conj( Integer i );					(since C++20)

1) Computes the complex conjugate of z by reversing the sign of the imaginary part.

A,B) Additional overloads are provided for all integer and floating-point types, which are treated as complex numbers with zero imaginary component.

(since C++11)

Parameters

z	-	complex value
f	-	floating-point value
i	-	integer value

Return value

1) The complex conjugate of z.

A) std::complex(f).

B) std::complex<double>(i).

Notes

The additional overloads are not required to be provided exactly as (A,B). They only need to be sufficient to ensure that for their argument num:

• If num has a standard(until C++23) floating-point type T, then std::conj(num) has the same effect as std::conj(std::complex<T>(num)).
• Otherwise, if num has an integer type, then std::conj(num) has the same effect as std::conj(std::complex<double>(num)).

Example

Run this code

#include <complex>
#include <iostream>
 
int main()
{
    std::complex<double> z(1.0, 2.0);
    std::cout << "The conjugate of " << z << " is " << std::conj(z) << '\n'
              << "Their product is " << z * std::conj(z) << '\n';
}

Output:

The conjugate of (1,2) is (1,-2)
Their product is (5,0)

See also

abs(std::complex)	returns the magnitude of a complex number (function template)
norm	returns the squared magnitude (function template)
polar	constructs a complex number from magnitude and phase angle (function template)
C documentation for conj