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Difference between revisions of "cpp/numeric/complex/conj"

From cppreference.com
< cpp‎ | numeric‎ | complex
(overloads from 26.4.9)
m (<double> z(1, 2) -> <double> z(1.0, 2.0))
 
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{{cpp/title|conj{{small|(std::complex)}}}}
 
{{cpp/title|conj{{small|(std::complex)}}}}
 
{{cpp/numeric/complex/navbar}}
 
{{cpp/numeric/complex/navbar}}
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{{ddcl list begin}}
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{{dcl begin}}
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{{ddcl list header | complex}}
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{{dcl header|complex}}
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{{ddcl list item | num=1 | 1=
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{{dcl rev multi|num=1|dcl1=
 
template< class T >  
 
template< class T >  
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complex<T> conj( const complex<T>& z );
+
std::complex<T> conj( const std::complex<T>& z );
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|since2=c++20|dcl2=
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template< class T >
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constexpr std::complex<T> conj( const std::complex<T>& z );
 
}}
 
}}
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{{ddcl list item | num=2 | notes={{mark since c++11}} | 1=
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{{dcl h|[[#Notes|Additional overloads]] {{mark since c++11}}}}
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std::complex<long double> conj( long double z );
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{{dcl header|complex}}
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{{dcl rev multi|num=A|dcl1=
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std::complex<float>      conj( float f );
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std::complex<double>      conj( double f );
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std::complex<long double> conj( long double f );
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|since2=c++20|dcl2=
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constexpr std::complex<float>      conj( float f );
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constexpr std::complex<double>      conj( double f );
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constexpr std::complex<long double> conj( long double f );
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|since3=c++23|dcl3=
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template< class FloatingPoint >
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constexpr std::complex<FloatingPoint> conj( FloatingPoint f );
 
}}
 
}}
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{{ddcl list item | num=3 | notes={{mark since c++11}} | 1=
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{{dcl rev multi|num=B|dcl1=
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template< class DoubleOrIngeter >
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template< class Integer >
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std::complex<double> conj( DoubleOrInteger z );
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constexpr std::complex<double> conj( Integer i );
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|since2=c++20|dcl2=
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template< class Integer >
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constexpr std::complex<double> conj( Integer i );
 
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}}
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{{dcl end}}
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std::complex<float> conj( float z );
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}}
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{{ddcl list end}}
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Returns the complex conjugate of the complex number {{tt|z}}.
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@1@ Computes the {{enwiki|Complex conjugate|complex conjugate}} of {{c|z}} by reversing the sign of the imaginary part.
  
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{{mark since c++11}}Additional overloads are provided for {{c|float}}, {{c|double}}, {{c|long double}}, and all integer types, which are treated as complex numbers with zero imaginary component.
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{{rrev|since=c++11|
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@A,B@ Additional overloads are provided for all integer and floating-point types, which are treated as complex numbers with zero imaginary component.
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}}
  
 
===Parameters===
 
===Parameters===
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{{param list begin}}
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{{par begin}}
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{{param list item | z | complex value}}
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{{par|z|complex value}}
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{{param list end}}
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{{par|f|floating-point value}}
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{{par|i|integer value}}
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{{par end}}
  
 
===Return value===
 
===Return value===
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@1@ The complex conjugate of {{c|z}}.
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@A@ {{c|std::complex(f)}}.
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@B@ {{c|std::complex<double>(i)}}.
  
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the complex conjugate of {{tt|z}}
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===Notes===
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{{cpp/numeric/complex/additional overload note|conj}}
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===Example===
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{{example|
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|code=
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#include <complex>
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#include <iostream>
 +
 
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int main()
 +
{
 +
    std::complex<double> z(1.0, 2.0);
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    std::cout << "The conjugate of " << z << " is " << std::conj(z) << '\n'
 +
              << "Their product is " << z * std::conj(z) << '\n';
 +
}
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|output=
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The conjugate of (1,2) is (1,-2)
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Their product is (5,0)
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}}
  
 
===See also===
 
===See also===
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{{dcl list template | cpp/numeric/complex/dcl list abs}}
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{{dsc inc|cpp/numeric/complex/dsc abs}}
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{{dsc inc|cpp/numeric/complex/dsc norm}}
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{{dcl list template | cpp/numeric/complex/dcl list polar}}
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{{dsc inc|cpp/numeric/complex/dsc polar}}
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{{dsc see c|c/numeric/complex/conj}}
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{{dsc end}}
  
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Latest revision as of 09:20, 21 April 2023

 
C++
 
Numerics library
Common mathematical functions
Mathematical special functions (C++17)
Mathematical constants (C++20)
Basic linear algebra algorithms (C++26)
Floating-point environment (C++11)
Complex numbers
Numeric array (valarray)
Pseudo-random number generation
Factor operations
(C++17)
(C++17)
Interpolations
(C++20)
(C++20)
Saturation arithmetic
(C++26)
(C++26)
(C++26)
(C++26)
(C++26)

Generic numeric operations
Bit operations
(C++20)    
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++20)
(C++23)
(C++20)
 
std::complex
 
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)

Contents

[edit] Parameters

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

[edit] Return value

1) The complex conjugate of z.
A) std::complex(f).
B) std::complex<double>(i).

[edit] 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)).

[edit] 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)

[edit] See also

 returns the magnitude of a complex number
(function template) [edit]
returns the squared magnitude
(function template) [edit]
constructs a complex number from magnitude and phase angle
(function template) [edit]
C documentation for conj
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