How to Create a Deque of Arrays in C++?

In C++, a deque (double-ended queue) is a data structure that allows insertion and deletion at both ends whereas arrays are fixed-size collections of elements. In this article, we will learn how to create a deque of arrays in C++ STL.

Example:

Input: 
myArray1 = {1, 4, 8, 9, 11} 
myArray2 = {1, 2, 3, 5, 7}

Output: 
myDeque: [ {1, 4, 8, 9, 11} {1, 2, 3, 5, 7} ]

Creating a Deque of Arrays in C++

To create a std::deque of std::array in C++, we can pass the type of the deque container to be of the type std::array as a template parameter while declaration.

Syntax to Create a Deque of Arrays in C++

deque<array<dataType, size>> dequeName;

Here,

• dataType denotes the data type of elements stored in the array.
• size denotes the size of the array.
• dequeName is a name of deque of arrays.

Note: We cannot create a deque of Plain Old Arrays as they do not meet the criteria for elements of deque containers which says that the elements should be at least copy constructible and assignable.

C++ Program to Create a Deque of Arrays

The below example demonstrates how we can create a deque of arrays in C++.

C++

// C++ Program to illustrate how to create a deque of array
#include <array>
#include <deque>
#include <iostream>
using namespace std;

int main()
{
    // Declaring a deque of arrays
    deque<array<int, 3> > myDeque;

    // Creating some arrays
    array<int, 3> arr1 = { 1, 2, 3 };
    array<int, 3> arr2 = { 4, 5, 6 };
    array<int, 3> arr3 = { 7, 8, 9 };

    // Pushing arrays into the deque
    myDeque.push_back(arr1);
    myDeque.push_back(arr2);
    myDeque.push_back(arr3);

    // Checking if the deque is empty
    cout << "myDeque: " << endl;
    int i = 1;
    for (auto& ele : myDeque) {
        cout << "Array" << i++ << ": ";
        for (auto i : ele) {
            cout << i << " ";
        }
        cout << endl;
    }

    return 0;
}

Output

myDeque: 
Array1: 1 2 3 
Array2: 4 5 6 
Array3: 7 8 9 

Time Complexity: O(N*M), where N is the number of arrays and M is the average size of each array.
Auxilliary Space: O(N*M)