valarray begin() function in C++

The begin() function is defined in valarray header file. This function returns an iterator pointing to the first element in the valarray v.

Syntax:

template< class T > 
    begin( valarray<T>& v );

Parameter: This function takes a mandatory parameter v which represents the valarray object.

Returns: This function returns the iterator to the first value in the valarray.

Below programs illustrate the above function:

Example 1:-

// C++ program to demonstrate
// example of begin() function.

#include <bits/stdc++.h>
using namespace std;

int main()
{
    // Initializing valarray
    valarray<int> varr = { 10, 20, 30, 40, 50 };

    cout << "valarray contains=";

    for (auto i = begin(varr); i != end(varr); i++) {
        cout << ' ' << *i;
    }

    cout << endl;

    return 0;
}

Output:

valarray contains= 10 20 30 40 50

Example 2:-

// C++ program to demonstrate
// example of begin() function.

#include <bits/stdc++.h>
using namespace std;

int main()
{
    // Initializing valarray
    valarray<int> varr = { -10, -20, -30, -40 };

    cout << "valarray contains=";

    for (auto i = begin(varr); i != end(varr); i++) {
        cout << ' ' << *i;
    }

    cout << endl;

    return 0;
}

Output:

valarray contains= -10 -20 -30 -40