Array class in C++

Array Class

In C++, the array class is part of the standard library and is known for its fixed size. The C++ array class, introduced in C++11, offers a better alternative to C-style arrays.

The following are the advantages of the array class over a C-style array:

• Array class knows its size, whereas a C-style array does not have its size. So when passing to functions, we don't need to pass the size of the array as a separate parameter.
• C-style array there is more risk of array being decayed into a pointer. Array classes don't decay into pointers
• C-style arrays (such as int arr[5]) may easily transform into pointers, losing their size information. When passing to functions. Unexpected behaviour may result from this. Array classes (such as std::array<int, 5>) protect against unexpected pointer decay by maintaining their size and structure. They are safer and have built-in features.
• Compared to C-style arrays, array classes are typically reliable, lightweight, and efficient.

Operation on Array

The following are functions to operate on an array:

• size(): To return the size of array i.e. returns the no of elements of the array.
• max_size(): To return maximum number of elements of the array.
• front(): To return front element of the array.
• back(): To return last element of the array.
• empty(): Returns true if array size is true otherwise false.
• fill(): To fill the entire array with a particular value.
• swap(): To swap the elements of one array to another.

Example to Get The Size of an Array

The following C++ example gives the size of an array using the size method:

#include <iostream>
using namespace std;
int main() {
   int arr[] = {1, 2, 3, 4, 5, 6};
   // use the size method
   int len = size(arr);
   cout << "Size of an Array: "<<len;
   return 0;
}

Following is the output of the code:

Size of an Array: 6

Example to Get Front and Back Elements

This is C++ code to demonstrate working of front() and back() methods of the array class:

#include<iostream>
#include<array> 
using namespace std;
int main()
{
   array<int,6> arr = {1, 2, 3, 4, 5, 6};
   // Display first element of array
   cout << "First element of array is : ";
   int &first=arr.front();
   cout <<first<< endl;
   
   // Display last element of array
   cout << "Last element of array is : ";
   int &last=arr.back();
   cout << last << endl;
   return 0;
}

Following is the output:

First element of array is : 1
Last element of array is : 6

Example to Return The Size and Max_Size

The following example demonstrates the working of the size() and the max_size() methods:

#include<iostream>
#include<array> 
using namespace std;
int main()
{
   array<int,5> arr = {1, 2, 3, 4, 5};
   
   cout << "Size of an array: ";
   cout <<arr.size()<< endl;
   
   cout << "maximum elements array can store: ";
   cout << arr.max_size() << endl;
   return 0;
}

Following is the output of the above code:

Size of an array: 5
maximum elements array can store: 5