std::indirect_array (3) - Linux Manuals

std::indirect_array: std::indirect_array

NAME

std::indirect_array - std::indirect_array

Synopsis

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

std::gslice_array is a helper template used by std::indirect_array subscript operator. It has reference semantics to a subset of the array specified by an indirect array (std::valarray<std::size_t> object).

Member types

Type Definition
value_type T

Member functions

              constructs a indirect_array
constructor (public member function)
              destroys a indirect_array
destructor (public member function)
              assigns contents
operator= (public member function)

operator+=
operator-=
operator*=
operator/= performs arithmetic operation on the array referred by indirect array.
operator%= (public member function)
operator&=
operator|=
operator^=
operator<<=
operator>>=

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 indexes '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