namespace std {
template<class T> class indirect_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;
indirect_array(const indirect_array&);
~indirect_array();
const indirect_array& operator=(const indirect_array&) const;
void operator=(const T&) const;
indirect_array() = delete;
};
}
This template is a helper template used by the indirect subscript operator
indirect_array<T> valarray<T>::operator[](const valarray<size_t>&).
It has reference semantics to a subset of an array specified by an
indirect_array.Thus, the expression
a[indirect] = b;
has the effect of assigning the elements of
b
to the elements in
a
whose indices appear in
indirect.