cppdraft_translate/cppdraft/template/indirect/array/overview.md

[template.indirect.array.overview]

29 Numerics library [numerics]

29.6 Numeric arrays [numarray]

29.6.9 Class template indirect_array [template.indirect.array]

29.6.9.1 Overview [template.indirect.array.overview]

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

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

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

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This template is a helper template used by the indirect subscript operator

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indirect_array<T> valarray<T>::operator[](const valarray<size_t>&);

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It has reference semantics to a subset of an array specified by anindirect_array.

Thus, the expressiona[​indirect] = b; has the effect of assigning the elements ofb to the elements ina whose indices appear inindirect.