29 Numerics library [numerics]

29.5 Complex numbers [complex.numbers]

29.5.10 Suffixes for complex number literals [complex.literals]

This subclause describes literal suffixes for constructing complex number literals.
The suffixes i, il, and if create complex numbers of the types complex<double>, complex<long double>, and complex<float> respectively, with their imaginary part denoted by the given literal number and the real part being zero.
constexpr complex<long double> operator""il(long double d); constexpr complex<long double> operator""il(unsigned long long d);
Returns: complex<long double>{0.0L, static_­cast<long double>(d)}.
constexpr complex<double> operator""i(long double d); constexpr complex<double> operator""i(unsigned long long d);
Returns: complex<double>{0.0, static_­cast<double>(d)}.
constexpr complex<float> operator""if(long double d); constexpr complex<float> operator""if(unsigned long long d);
Returns: complex<float>{0.0f, static_­cast<float>(d)}.