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

 

C++

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Technical specifications

Symbols index

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Numerics library

Common mathematical functions
Mathematical special functions (C++17)
Mathematical constants (C++20)
Basic linear algebra algorithms (C++26)
Floating-point environment (C++11)
Complex numbers
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gcd (C++17)	lcm (C++17)
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midpoint (C++20)	lerp (C++20)
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add_sat (C++26) sub_sat (C++26) saturate_cast (C++26)	mul_sat (C++26) div_sat (C++26)
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iota (C++11) ranges::iota (C++23) accumulate inner_product adjacent_difference partial_sum	reduce (C++17) transform_reduce (C++17) inclusive_scan (C++17) exclusive_scan (C++17) transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)
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has_single_bit (C++20)     bit_cast (C++20) bit_ceil (C++20) bit_floor (C++20) bit_width (C++20) rotl (C++20) rotr (C++20)	popcount (C++20) countl_zero (C++20) countl_one (C++20) countr_zero (C++20) countr_one (C++20) byteswap (C++23) endian (C++20)

 

std::complex

Member functions
complex::complex complex::operator= complex::real complex::imag	complex::operator+=complex::operator-=complex::operator*=complex::operator/=
Non-member functions
operator+operator- operator+operator-operator*operator/ operator==operator!= (until C++20)   operator<<operator>> get(std::complex) (C++26)	real imag abs arg norm conj proj (C++11) polar operator""ioperator""ifoperator""il (C++14)(C++14)(C++14)
Exponential functions
log   log10   exp
Power functions
pow   sqrt
Trigonometric functions
sin   cos tan asin (C++11) acos (C++11) atan (C++11)
Hyperbolic functions
sinh   cosh tanh asinh (C++11) acosh (C++11) atanh (C++11)
Helper types
tuple_size<std::complex> (C++26)
tuple_element<std::complex> (C++26)

 

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 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.

Feature-test macro	Value	Std	Feature
__cpp_lib_complex_udls	201309L	(C++14)	User-Defined Literals for std::complex

Possible implementation

operator""i
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)}; }
operator""if
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)}; }
operator""il
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 <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';
}

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)
C documentation for I