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// valarray::operator[] example
#include <iostream> // std::cout
#include <valarray> // std::valarray, std::slice, std::gslice
int main ()
{
std::valarray<int> myarray (10); // 0 0 0 0 0 0 0 0 0 0
// slice:
myarray[std::slice(2,3,3)]=10; // 0 0 10 0 0 10 0 0 10 0
// gslice:
size_t lengths[]={2,2};
size_t strides[]={6,2};
myarray[std::gslice(1, std::valarray<size_t>(lengths,2), std::valarray<size_t>(strides,2))]=20;
// 0 20 10 20 0 10 0 20 10 20
// mask:
std::valarray<bool> mymask (10);
for (int i=0; i<10; ++i) mymask[i]= ((i%2)==0);
myarray[mymask] += std::valarray<int>(3,5); // 3 20 13 20 3 10 3 20 13 20
//indirect:
size_t sel[]= {2,5,7};
std::valarray<size_t> myselection (sel,3); // 3 20 99 20 3 99 3 99 13 20
myarray[myselection]=99;
std::cout << "myarray: ";
for (size_t i=0; i<myarray.size(); ++i)
std::cout << myarray[i] << ' ';
std::cout << '\n';
return 0;
}
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