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

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