[complex.members]

# 29 Numerics library [[numerics]](./#numerics)

## 29.4 Complex numbers [[complex.numbers]](complex.numbers#complex.members)

### 29.4.4 Member functions [complex.members]

[🔗](#lib:complex,constructor)

`constexpr complex(const T& re = T(), const T& im = T());
`

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L366)

*Postconditions*: real() == re && imag() == im is true[.](#1.sentence-1)

[🔗](#lib:complex,constructor_)

`template<class X> constexpr explicit(see below) complex(const complex<X>& other);
`

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L377)

*Effects*: Initializes the real part with other.real() and
the imaginary part with other.imag()[.](#2.sentence-1)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L382)

*Remarks*: The expression inside explicit evaluates to false if and only if the floating-point conversion rank of T is greater than or equal to the floating-point conversion rank of X[.](#3.sentence-1)

[🔗](#lib:real,complex)

`constexpr T real() const;
`

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L395)

*Returns*: The value of the real component[.](#4.sentence-1)

[🔗](#lib:real,complex_)

`constexpr void real(T val);
`

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L406)

*Effects*: Assigns val to the real component[.](#5.sentence-1)

[🔗](#lib:imag,complex)

`constexpr T imag() const;
`

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L417)

*Returns*: The value of the imaginary component[.](#6.sentence-1)

[🔗](#lib:imag,complex_)

`constexpr void imag(T val);
`

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L428)

*Effects*: Assigns val to the imaginary component[.](#7.sentence-1)