operator==,!= (std::complex)

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std::complex
Defined in header <complex>
(1)
template < class T >
bool operator == ( const complex < T > & lhs, const complex < T > & rhs ) ;
(until C++14)
template < class T >
constexpr bool operator == ( const complex < T > & lhs, const complex < T > & rhs ) ;
(since C++14)
(2)
template < class T >
bool operator == ( const complex < T > & lhs, const T & rhs ) ;
(until C++14)
template < class T >
constexpr bool operator == ( const complex < T > & lhs, const T & rhs ) ;
(since C++14)
(3)
template < class T >
bool operator == ( const T & lhs, const complex < T > & rhs ) ;
(until C++14)
template < class T >
constexpr bool operator == ( const T & lhs, const complex < T > & rhs ) ;
(since C++14)
(until C++20)
(4)
template < class T >
bool operator ! = ( const complex < T > & lhs, const complex < T > & rhs ) ;
(until C++14)
template < class T >
constexpr bool operator ! = ( const complex < T > & lhs, const complex < T > & rhs ) ;
(since C++14)
(until C++20)
(5)
template < class T >
bool operator ! = ( const complex < T > & lhs, const T & rhs ) ;
(until C++14)
template < class T >
constexpr bool operator ! = ( const complex < T > & lhs, const T & rhs ) ;
(since C++14)
(until C++20)
(6)
template < class T >
bool operator ! = ( const T & lhs, const complex < T > & rhs ) ;
(until C++14)
template < class T >
constexpr bool operator ! = ( const T & lhs, const complex < T > & rhs ) ;
(since C++14)
(until C++20)

Compares two complex numbers. Scalar arguments are treated as complex numbers with the real part equal to the argument and the imaginary part set to zero.

1-3) Compares lhs and rhs for equality.
4-6) Compares lhs and rhs for inequality.

The != operator is synthesized from operator== .

(since C++20)

Parameters

lhs, rhs - the arguments to compare: either both complex numbers or one complex and one scalar of matching type ( float , double , long double )

Return value

1-3) true if respective parts of lhs are equal to rhs , false otherwise.
4-6) ! ( lhs == rhs )

Example

Run this code 
#include <complex>
 
int main()
{
    using std::operator""i; // or: using namespace std::complex_literals;
 
    static_assert(1.0i == 1.0i);
    static_assert(2.0i != 1.0i);
 
    constexpr std::complex z(1.0, 0.0);
    static_assert(z == 1.0);
    static_assert(1.0 == z);
    static_assert(2.0 != z);
    static_assert(z != 2.0);
}
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