C++ valarray Library - Function constructor

Description

It constructs a valarray object.

Declaration

Following is the declaration for std::valarray::valarray function.

valarray();

C++11

valarray();

Parameters

• n − It is a length of array.

• val − It is a value to which each of the elements is initialized.

• p − It is a pointer to an array of elements.

• x − It is a valarray object of the same type.

• sub − The result of a valarray subscripting operation.

• il − It is an initializer_list object.

Return Value

none

Exceptions

Basic guarantee − if any operation performed on the elements throws an exception.

Data races

All elements effectively copied are accessed.

Example

In below example explains about std::valarray::valarray function.

#include <iostream>
#include <valarray>

int main () {
   int init[]= {10,50,30,60};
   std::valarray<int> first;
   std::valarray<int> second (5);
   std::valarray<int> third (10,3);
   std::valarray<int> fourth (init,4);
   std::valarray<int> fifth (fourth);
   std::valarray<int> sixth (fifth[std::slice(1,2,1)]);

   std::cout << "sixth sums " << sixth.sum() << '\n';

   return 0;
}

Let us compile and run the above program, this will produce the following result −

sixth sums 80