C++ valarray Library - Function constructor

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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