C++ valarray Library - Function size

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Description

It returns the number of elements in the valarray.

Declaration

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

size_t size() const;

C++11

size_t size() const;

Parameters

none

Return Value

It returns the number of elements in the valarray.

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::size function.

#include <iostream>
#include <valarray>

int main () {
   std::valarray<int> myvalarray;
   std::cout << "1. After construction: " << myvalarray.size() << '\n';

   myvalarray = std::valarray<int>(15);
   std::cout << "2. After assignment: " << myvalarray.size() << '\n';

   myvalarray.resize(30);
   std::cout << "3. After downsizing: " << myvalarray.size() << '\n';

   myvalarray.resize(100);
   std::cout << "4. After resizing up: " << myvalarray.size() << '\n';

   return 0;
}

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

1. After construction: 0
2. After assignment: 15
3. After downsizing: 30
4. After resizing up: 100