NAME¶

std::literals::complex_literals::operator""i,operator""if,operator""il - std::literals::complex_literals::operator""i,operator""if,operator""il

Synopsis¶

Defined in header <complex>
constexpr complex<double> operator""i( long double arg ); (1) (since C++14)
constexpr complex<double> operator""i( unsigned long long arg );
constexpr complex<float> operator""if( long double arg ); (2) (since C++14)
constexpr complex<float> operator""if( unsigned long long arg );
constexpr complex<long double> operator""il( long double arg );
constexpr complex<long double> operator""il( unsigned long long (3) (since C++14)
arg );

Forms a std::complex literal representing an imaginary number.

1) Forms a literal std::complex<double> with the real part zero and imaginary part
arg.
2) Forms a literal std::complex<float> with the real part zero and imaginary part
arg.
3) Forms a literal std::complex<long double> with the real part zero and imaginary
part arg.

Parameters¶

arg - the value of the imaginary number

Return value¶

The std::complex literal with the real part zero and imaginary part arg.

Notes¶

These operators are declared in the namespace std::literals::complex_literals, where
both literals and complex_literals are inline namespaces. Access to these operators
can be gained with either:

* using namespace std::literals,
* using namespace std::complex_literals, or
* using namespace std::literals::complex_literals.

Even though if is a keyword in C++, it is a ud-suffix of the literal operator of the
form operator ""if and in the literal expressions such as 1if or 1.0if because it is
not separated by whitespace and is not a standalone token.

Feature-test macro Value Std Feature
__cpp_lib_complex_udls 201309L (C++14) User-Defined Literals for std::complex

Possible implementation¶

operator""i
constexpr std::complex<double> operator""i(unsigned long long d)
{
return std::complex<double> {0.0, static_cast<double>(d)};
}

constexpr std::complex<double> operator""i(long double d)
{
return std::complex<double> {0.0, static_cast<double>(d)};
}
operator""if
constexpr std::complex<float> operator""if(unsigned long long d)
{
return std::complex<float> {0.0f, static_cast<float>(d)};
}

constexpr std::complex<float> operator""if(long double d)
{
return std::complex<float> {0.0f, static_cast<float>(d)};
}
operator""il
constexpr std::complex<long double> operator""il(unsigned long long d)
{
return std::complex<long double> {0.0L, static_cast<long double>(d)};
}

constexpr std::complex<long double> operator""il(long double d)
{
return std::complex<long double> {0.0L, d};
}

Example¶

// Run this code

#include <complex>
#include <iostream>

int main()
{
using namespace std::complex_literals;

std::complex<double> c = 1.0 + 1i;
std::cout << "abs" << c << " = " << std::abs(c) << '\n';

std::complex<float> z = 3.0f + 4.0if;
std::cout << "abs" << z << " = " << std::abs(z) << '\n';
}

Output:¶

abs(1,1) = 1.41421
abs(3,4) = 5

See also¶

constructor constructs a complex number
(public member function)
operator= assigns the contents
(public member function)
C documentation for
I