std::literals::complex_literals::operators

Defined in header <complex>

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

(1)

(since C++14)

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

(2)

(since C++14)

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

(3)

(since C++14)

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.

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

#include <iostream>
#include <complex>
  
int main()
{
    using namespace std::complex_literals;
    std::complex<double> c = 1.0 + 1i;
    std::cout << "abs" << c << " = " << abs(c) << '\n';
}

Output:

1	`abs(1,1) = 1.41421`

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

std::literals::complex_literals::operators

Parameters

Return value

Notes

Possible implementation

Example

See also