#include<iostream>#include<valarray>intmain(){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(intn: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(intn:data)std::cout<<n<<' ';std::cout<<'\n';}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