C++ Array::begin() Function

The C++ std::array::begin() function is used to return an iterator pointing to the first element of the array. It allows traversal or manipulation of elements from the start of an array.

This function can be used in both constant and non-constant contexts, meaning it has two overloads: one returning a constant iterator and another returning non-constant iterator.

Syntax

Following is the syntax for std::array::begin() function.

iterator begin() noexcept;
const_iterator begin() const noexcept;

Parameters

It does not accepts any parameter.

Return Value

This function returns an iterator to the beginning of the sequence.

Exceptions

This function never throws exception.

Time complexity

Constant i.e. O(1)

Example 1

In the following example, we are going to consider the basic usage of the begin() function.

#include <iostream>
#include <array>
using namespace std;
int main(void) {
   array < int, 5 > arr = {1,2,3,4,5};
   auto itr = arr.begin();
   while (itr != arr.end()) {
      cout << * itr << " ";
      ++itr;
   }
   cout << endl;
   return 0;
}

Output

Output of the above code is as follows −

1 2 3 4 5

Example 2

Consider the another example, where we are going to use the begin() function on the array of characters.

#include <iostream>
#include <array>
using namespace std;
int main() {
   array < char, 5 > myarray {'P','R','A','S','U'};
   for (auto it = myarray.begin(); it != myarray.end(); ++it)
      cout << ' ' << * it;
   return 0;
}

Output

Following is the output of the above code −

P R A S U