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

From cppreference.com
< cpp‎ | numeric‎ | complex
m (langlinks)
m (<double> z(1, 2) -> <double> z(1.0, 2.0))
 
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{{cpp/numeric/complex/navbar}}
 
{{cpp/numeric/complex/navbar}}
 
{{dcl begin}}
 
{{dcl begin}}
−
{{dcl header | complex}}
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{{dcl header|complex}}
−
{{dcl rev multi | num=1 | until1=c++20 | dcl1=
+
{{dcl rev multi|num=1|dcl1=
 
template< class T >  
 
template< class T >  
 
std::complex<T> conj( const std::complex<T>& z );
 
std::complex<T> conj( const std::complex<T>& z );
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constexpr std::complex<T> conj( const std::complex<T>& z );
 
constexpr std::complex<T> conj( const std::complex<T>& z );
 
}}
 
}}
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{{dcl rev multi | num=2 | since1=c++11 | dcl1=
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{{dcl h|[[#Notes|Additional overloads]] {{mark since c++11}}}}
−
std::complex<float> conj( float z );
+
{{dcl header|complex}}
−
template< class DoubleOrInteger >
+
{{dcl rev multi|num=A|dcl1=
−
std::complex<double> conj( DoubleOrInteger z );
+
std::complex<float>       conj( float f );
−
std::complex<long double> conj( long double z );
+
std::complex<double>     conj( double f );
 +
std::complex<long double> conj( long double f );
 
|since2=c++20|dcl2=
 
|since2=c++20|dcl2=
−
constexpr std::complex<float> conj( float z );
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constexpr std::complex<float>       conj( float f );
−
template< class DoubleOrInteger >
+
constexpr std::complex<double>      conj( double f );
−
constexpr std::complex<double> conj( DoubleOrInteger z );
+
constexpr std::complex<long double> conj( long double f );
−
constexpr std::complex<long double> conj( long double z );
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|since3=c++23|dcl3=
 +
template< class FloatingPoint >
 +
constexpr std::complex<FloatingPoint> conj( FloatingPoint f );
 +
}}
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{{dcl rev multi|num=B|dcl1=
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template< class Integer >
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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 >
 +
constexpr std::complex<double> conj( Integer i );
 
}}
 
}}
 
{{dcl end}}
 
{{dcl end}}
  
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@1@ Computes the [[enwiki:Complex_conjugate|complex conjugate]] of {{tt|z}} by reversing the sign of the imaginary part.
+
@1@ Computes the {{enwiki|Complex conjugate|complex conjugate}} of {{c|z}} by reversing the sign of the imaginary part.
  
 
{{rrev|since=c++11|
 
{{rrev|since=c++11|
−
@2@ 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.
+
@A,B@ Additional overloads are provided for all integer and floating-point types, which are treated as complex numbers with zero imaginary component.
 
}}
 
}}
  
 
===Parameters===
 
===Parameters===
 
{{par begin}}
 
{{par begin}}
−
{{par | z | complex value}}
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{{par|z|complex value}}
 +
{{par|f|floating-point value}}
 +
{{par|i|integer value}}
 
{{par end}}
 
{{par end}}
  
 
===Return value===
 
===Return value===
 +
@1@ The complex conjugate of {{c|z}}.
 +
@A@ {{c|std::complex(f)}}.
 +
@B@ {{c|std::complex<double>(i)}}.
  
−
The complex conjugate of {{tt|z}}
+
===Notes===
 +
{{cpp/numeric/complex/additional overload note|conj}}
  
 
===Example===
 
===Example===
 
{{example|
 
{{example|
 
|code=
 
|code=
−
#include <iostream>
 
 
#include <complex>
 
#include <complex>
 +
#include <iostream>
  
 
int main()
 
int main()
 
{
 
{
−
     std::complex<double> z(1,2);
+
     std::complex<double> z(1.0, 2.0);
 
     std::cout << "The conjugate of " << z << " is " << std::conj(z) << '\n'
 
     std::cout << "The conjugate of " << z << " is " << std::conj(z) << '\n'
−
               << "Their product is " << z*std::conj(z) << '\n';
+
               << "Their product is " << z * std::conj(z) << '\n';
 
}
 
}
 
|output=
 
|output=
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===See also===
 
===See also===
 
{{dsc begin}}
 
{{dsc begin}}
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{{dsc inc | cpp/numeric/complex/dsc 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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{{dsc inc|cpp/numeric/complex/dsc norm}}
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{{dsc inc | cpp/numeric/complex/dsc polar}}
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{{dsc inc|cpp/numeric/complex/dsc polar}}
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{{dsc see c | c/numeric/complex/conj}}
+
{{dsc see c|c/numeric/complex/conj}}
 
{{dsc end}}
 
{{dsc end}}
  
 
{{langlinks|de|es|fr|it|ja|pt|ru|zh}}
 
{{langlinks|de|es|fr|it|ja|pt|ru|zh}}

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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