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

constexpr complex<double> operator""i( long double arg );
constexpr complex<double> operator""i( unsigned long long arg );

constexpr complex<float> operator""if( long double arg );
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 arg );

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

Parameters

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.

Possible implementation

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)};
}

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)};
}

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

#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';
}

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

See also