[template.slice.array]

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

## 29.6 Numeric arrays [[numarray]](numarray#template.slice.array)

### 29.6.5 Class template slice_array [template.slice.array]

#### [29.6.5.1](#overview) Overview [[template.slice.array.overview]](template.slice.array.overview)

[🔗](#lib:slice_array)

namespace std {template<class T> class slice_array {public:using value_type = T; void operator= (const valarray<T>&) const; void operator*= (const valarray<T>&) const; void operator/= (const valarray<T>&) const; void operator%= (const valarray<T>&) const; void operator+= (const valarray<T>&) const; void operator-= (const valarray<T>&) const; void operator^= (const valarray<T>&) const; void operator&= (const valarray<T>&) const; void operator|= (const valarray<T>&) const; void operator<<=(const valarray<T>&) const; void operator>>=(const valarray<T>&) const;

 slice_array(const slice_array&); ~slice_array(); const slice_array& operator=(const slice_array&) const; void operator=(const T&) const;

 slice_array() = delete; // as implied by declaring copy constructor above};}

[1](#overview-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8504)

This template is a helper template used by theslice subscript operatorslice_array<T> valarray<T>::operator[](slice);

[2](#overview-2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8511)

It has reference semantics to a subset of an array specified by aslice object[.](#overview-2.sentence-1)

[*Example [1](#overview-example-1)*:

The expressiona[slice(1, 5, 3)] = b; has the effect of assigning the elements ofb to a slice of the elements ina[.](#overview-2.sentence-2)

For the slice shown, the elements
selected froma are 1,4,…,13[.](#overview-2.sentence-3)

— *end example*]

#### [29.6.5.2](#slice.arr.assign) Assignment [[slice.arr.assign]](slice.arr.assign)

[🔗](#lib:operator=,slice_array)

`void operator=(const valarray<T>&) const;
const slice_array& operator=(const slice_array&) const;
`

[1](#slice.arr.assign-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8537)

These assignment operators have reference semantics,
assigning the values of the argument array elements to selected
elements of thevalarray<T> object to which theslice_array object refers[.](#slice.arr.assign-1.sentence-1)

#### [29.6.5.3](#slice.arr.comp.assign) Compound assignment [[slice.arr.comp.assign]](slice.arr.comp.assign)

[🔗](#lib:operator*=,slice_array)

`void operator*= (const valarray<T>&) const;
void operator/= (const valarray<T>&) const;
void operator%= (const valarray<T>&) const;
void operator+= (const valarray<T>&) const;
void operator-= (const valarray<T>&) const;
void operator^= (const valarray<T>&) const;
void operator&= (const valarray<T>&) const;
void operator|= (const valarray<T>&) const;
void operator<<=(const valarray<T>&) const;
void operator>>=(const valarray<T>&) const;
`

[1](#slice.arr.comp.assign-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8573)

These compound assignments have reference semantics, applying the
indicated operation to the elements of the argument array
and selected elements of thevalarray<T> object to which theslice_array object refers[.](#slice.arr.comp.assign-1.sentence-1)

#### [29.6.5.4](#slice.arr.fill) Fill function [[slice.arr.fill]](slice.arr.fill)

[🔗](#lib:operator=,slice_array_)

`void operator=(const T&) const;
`

[1](#slice.arr.fill-1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L8591)

This function has reference semantics, assigning the value of its argument
to the elements of thevalarray<T> object to which theslice_array object refers[.](#slice.arr.fill-1.sentence-1)