# std::real(std::complex)

From cppreference.com
< cpp‎ | numeric‎ | complex

Defined in header `<complex>` |  |
| (1) |
template< class T > T real( const std::complex<T>& z ); |  | (until C++14)
template< class T > constexpr T real( const std::complex<T>& z ); |  | (since C++14)
Additional overloads (since C++11) |  |
Defined in header `<complex>` |  |
| (A) |
float real( float f ); double real( double f ); long double real( long double f ); |  | (until C++14)
constexpr float real( float f ); constexpr double real( double f ); constexpr long double real( long double f ); |  | (since C++14) (until C++23)
template< class FloatingPoint > constexpr FloatingPoint real( FloatingPoint f ); |  | (since C++23)
| (B) |
template< class Integer > double real( Integer i ); |  | (until C++14)
template< class Integer > constexpr double real( Integer i ); |  | (since C++14)

1) Returns the real part of the complex number z, i.e. z.real().

A,B) Additional overloads are provided for all integer and floating-point types, which are treated as complex numbers with zero imaginary part. | (since C++11)

### Parameters

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

### Return value

1) The real part of z.
A) f.
B) static_cast<double>(i).

### 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::real(num) has the same effect as std::real(std::complex<T>(num)).
- Otherwise, if num has an integer type, then std::real(num) has the same effect as std::real(std::complex<double>(num)).

### See also

real | accesses the real part of the complex number (public member function)
imag | returns the imaginary part (function template)

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/numeric/complex/real2&oldid=149031"