std:: abs (std::complex)

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C++
Numerics library
Common mathematical functions
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Basic linear algebra algorithms (C++26)
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(C++20)
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std::complex
Defined in header <complex>
template < class T >
T abs ( const complex < T > & z ) ;

Returns the magnitude of the complex number z .

Parameters

z - complex value

Return value

If no errors occur, returns the absolute value (also known as norm, modulus, or magnitude) of z .

Errors and special cases are handled as if the function is implemented as std:: hypot ( std:: real ( z ) , std:: imag ( z ) ) .

Example

Run this code 
#include <complex>
#include <iostream>
 
int main()
{
    std::complex<double> z(1, 1);
    std::cout << z << " cartesian is rho = " << std::abs(z)
              << " theta = " << std::arg(z) << " polar\n";
}

Output: 

(1,1) cartesian is rho = 1.41421 theta = 0.785398 polar

See also

returns the phase angle
(function template)
constructs a complex number from magnitude and phase angle
(function template)
(C++11)
computes absolute value of an integral value ( |x| )
(function)
(C++11) (C++11)
absolute value of a floating point value ( |x| )
(function)
(C++11) (C++11) (C++11)
computes square root of the sum of the squares of two or three (since C++17) given numbers ( √ x 2 +y 2 ) , ( √ x 2 +y 2 +z 2 ) (since C++17)
(function)
applies the function abs to each element of valarray
(function template)
C documentation for cabs
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