std::indirect_array

 

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valarray::valarray valarray::~valarray valarray::operator= valarray::operator[] valarray::swap valarray::size valarray::resize valarray::sum valarray::min valarray::max valarray::shift valarray::cshift valarray::apply	valarray::operator+valarray::operator-valarray::operator~valarray::operator! valarray::operator+=valarray::operator-=valarray::operator*=valarray::operator/=valarray::operator%=valarray::operator&=valarray::operator|=valarray::operator^=valarray::operator<<=valarray::operator>>=
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std::indirect_array

Member functions

indirect_array::indirect_array

indirect_array::~indirect_array

indirect_array::operator=

indirect_array::operator+=indirect_array::operator-=indirect_array::operator*=indirect_array::operator/=indirect_array::operator%=indirect_array::operator&=indirect_array::operator|=indirect_array::operator^=indirect_array::operator<<=indirect_array::operator>>=

 

Defined in header <valarray>
template<class T >class indirect_array;

std::indirect_array is a helper template used by the valarray subscript operator with std::valarray<std::size_t> argument. It has reference semantics to a subset of the array whose indices specified by the std::valarray<std::size_t> object.

Member types

Type	Definition
value_type	T

Member functions

(constructor)	constructs a indirect_array (public member function)
(destructor)	destroys a indirect_array (public member function)
operator=	assigns contents (public member function)
operator+=operator-=operator*=operator/=operator%=operator&=operator|=operator^=operator<<=operator>>=	performs arithmetic operation on the array referred by indirect array. (public member function)

Example

Run this code

#include <iostream>#include <valarray>   int main(){std::valarray<int> data{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};   std::valarray<std::size_t> idx{0, 2, 4, 6, 8};   std::cout<<"Original valarray: ";for(int n : data)std::cout<< n <<' ';std::cout<<'\n';   data[idx]+= data[idx];// double the values at indices 'idx'   // the type of data[idx] is std::indirect_array<int>   std::cout<<"After indirect modification: ";for(int n : data)std::cout<< n <<' ';std::cout<<'\n';}

Output:

Original valarray: 0 1 2 3 4 5 6 7 8 9 After indirect modification: 0 1 4 3 8 5 12 7 16 9