Array class in C++ STL

Arrays are fixed-size sequence containers: they hold a specific number of elements ordered in a strict linear sequence.

The introduction of array class from C++11 has offered a better alternative for C-style arrays. The advantages of array class over C-style array are :-

• Array classes knows its own size, whereas C-style arrays lack this property. So when passing to functions, we don’t need to pass size of Array as a separate parameter.
• With C-style array there is more risk of array being decayed into a pointer. Array classes don’t decay into pointers
• Array classes are generally more efficient, light-weight and reliable than C-style arrays.

Functions of array :-

Iterators
begin : Return iterator to beginning (public member function )
end : Return iterator to end (public member function )
rbegin : Return reverse iterator to reverse beginning (public member function )
rend : Return reverse iterator to reverse end (public member function )
cbegin : Return const_iterator to beginning (public member function )
cend : Return const_iterator to end (public member function )
crbegin : Return const_reverse_iterator to reverse beginning (public member function )
crend : Return const_reverse_iterator to reverse end (public member function )

Capacity
size : Return size (public member function )
max_size : Return maximum size (public member function )
empty : Test whether array is empty (public member function )

Element access
operator[] : Access element (public member function )
at : Access element (public member function )
front : Access first element (public member function )
back : Access last element (public member function )
data : Get pointer to data (public member function )

Modifiers
fill : Fill array with value (public member function )
swap : Swap content (public member function )

// C++ code to demonstrate working of array
// Function at(), get(), front(), back(), size(), max_size() and operator[]
#include<iostream>
#include<array> // for array, at()
#include<tuple> // for get()
using namespace std;
int main()
{
	// Initializing the array elements
	array<int,6> ar = {1, 2, 3, 4, 5, 6};
	// Printing array elements using at()
	cout << "The array elements are (using at()) : ";
	for ( int i=0; i<6; i++)
	cout << ar.at(i) << " ";
	cout << endl;
	// Printing array elements using get()
	cout << "The array elements are (using get()) : ";
	cout << get<0>(ar) << " " << get<1>(ar) << " ";
	cout << get<2>(ar) << " " << get<3>(ar) << " ";
	cout << get<4>(ar) << " " << get<5>(ar) << " ";
	cout << endl;
	// Printing first element of array
        cout << "First element of array is : ";
        cout << ar.front() << endl;
        // Printing last element of array
        cout << "Last element of array is : ";
        cout << ar.back() << endl;
	// Printing array elements using operator[]
	cout << "The array elements are (using operator[]) : ";
	for ( int i=0; i<6; i++)
	cout << ar[i] << " ";
	cout << endl;
	// Printing number of array elements
        cout << "The number of array elements is : ";
        cout << ar.size() << endl;
        // Printing maximum elements array can hold
        cout << "Maximum elements array can hold is : ";
        cout << ar.max_size() << endl;
	
	return 0;
}

/*
Output : 
The array elements are (using at()) : 1 2 3 4 5 6 
The array elements are (using get()) : 1 2 3 4 5 6 
First element of array is : 1
Last element of array is : 6
The array elements are (using operator[]) : 1 2 3 4 5 6 
The number of array elements is : 6
Maximum elements array can hold is : 6
*/

// C++ code to demonstrate working of swap()
#include<iostream>
#include<array> // for swap() and array
using namespace std;
int main()
{
	// Initializing 1st array
	array<int,6> ar = {1, 2, 3, 4, 5, 6};

	// Initializing 2nd array
	array<int,6> ar1 = {7, 8, 9, 10, 11, 12};

	// Printing 1st and 2nd array before swapping
	cout << "The first array elements before swapping are : ";
	for (int i=0; i<6; i++)
	cout << ar[i] << " ";
	cout << endl;
	cout << "The second array elements before swapping are : ";
	for (int i=0; i<6; i++)
	cout << ar1[i] << " ";
	cout << endl;

	// Swapping ar1 values with ar
	ar.swap(ar1);

	// Printing 1st and 2nd array after swapping
	cout << "The first array elements after swapping are : ";
	for (int i=0; i<6; i++)
	cout << ar[i] << " ";
	cout << endl;
	cout << "The second array elements after swapping are : ";
	for (int i=0; i<6; i++)
	cout << ar1[i] << " ";
	cout << endl;
	return 0;
}

/*
Output : 
The first array elements before swapping are : 1 2 3 4 5 6 
The second array elements before swapping are : 7 8 9 10 11 12 
The first array elements after swapping are : 7 8 9 10 11 12 
The second array elements after swapping are : 1 2 3 4 5 6 
*/

// C++ code to demonstrate working of empty() and fill()
#include<iostream>
#include<array> // for fill() and empty()
using namespace std;
int main()
{
	// Declaring 1st array
	array<int,6> ar;
	// Declaring 2nd array
	array<int,0> ar1;
	// Checking size of array if it is empty
	ar1.empty()? cout << "Array empty":
		cout << "Array not empty";
	cout << endl;
	// Filling array with 0
	ar.fill(0);
	// Displaying array after filling
	cout << "Array after filling operation is : ";
	for ( int i=0; i<6; i++)
		cout << ar[i] << " ";
	return 0;
}

/*
Output : 
Array empty
Array after filling operation is : 0 0 0 0 0 0 
*/