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 using namespace std::literals, using namespace
std::complex_literals, and 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: __cpp_lib_complex_udls

Possible implementation¶

First version¶

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)};
}

Second version¶

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)};
}
Third version
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 <iostream>
#include <complex>

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)