Defined in header <complex>  

template< class T > T norm( const complex<T>& z );  (1)  
long double norm( long double z );  (2)  (since C++11) 
template< class DoubleOrInteger > double norm( DoubleOrInteger z );  (3)  (since C++11) 
float norm( float z );  (4)  (since C++11) 
Returns the squared magnitude of the complex number z
.
(since C++11)Additional overloads are provided for float
, double
, long double
, and all integer types, which are treated as complex numbers with zero imaginary component.
z    complex value 
the squared magnitude of z
.
The norm calculated by this function is also known as field norm or absolute square.
The Euclidean norm of a complex number is provided by std::abs
, which is more costly to compute. In some situations, it may be replaced by std::norm
, for example, if abs(z1) > abs(z2)
then norm(z1) > norm(z2)
.
returns the magnitude of a complex number (function template) 

returns the complex conjugate (function template) 

constructs a complex number from magnitude and phase angle (function template) 
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