class

std::slice

class slice;

Valarray slice selector

This class represents a valarray slice selector. It does not contain nor refers to any element - it only describes a selection of elements to be used as an index in valarray::operator[] .

A valarray slice is defined by a starting index, a size, and a stride.

The starting index (start ) is the index of the first element in the selection.
The size (size ) is the number of elements in the selection.
The stride (stride ) is the span that separates the elements selected.

Therefore, a slice with a stride higher than 1 does not select contiguous elements in the valarray ; For example, slice(3,4,5) selects the elements 3, 8, 13 and 18.

Member functions

(constructor): slice constructor (public member function)

slice::start: Return start of slice (public member function)

slice::size: Return size of slice (public member function)

slice::stride: Return stride of slice (public member function)

Example

// slice example
#include <iostream> // std::cout
#include <cstddef> // std::size_t
#include <valarray> // std::valarray, std::slice
int main ()
{
 std::valarray<int> foo (12);
 for (int i=0; i<12; ++i) foo[i]=i;
 std::valarray<int> bar = foo[std::slice(2,3,4)];
 std::cout << "slice(2,3,4):";
 for (std::size_t n=0; n<bar.size(); n++)
	 std::cout << ' ' << bar[n];
 std::cout << '\n';
 return 0;
}

Output


slice(2,3,4): 2 6 10

classes

functions

member functions

std::slice

Member functions

Example

See also