How to Remove an Element from Front of Deque in C++?

In C++, a deque (double-ended queue) is a data structure that allows efficient insertion and deletion at both ends. In this article, we will learn to remove an element from the beginning of a deque in C++.

Example:

Input:
myDeque = {1, 2, 3, 4, 5};

Output:
Deque After Removal: 2 3 4 5

Removing the First Element from a Deque in C++

To remove an element from the beginning of a deque in C++, we can use the std::deque::pop_front() member function of std::deque that dequeues the first element, effectively removing it from the deque.

Syntax to Use std::deque::pop_front

dequeName.pop_front();

C++ Program to Remove an Element from the Beginning of a Deque

The below program demonstrates how we can remove the first element from the beginning of a deque in C++.

C++

// C++ Program to demonstrates how we can remove the first
// element from the beginning of a deque
#include <deque>
#include <iostream>
using namespace std;

int main()
{
    // Creating a deque
    deque<int> myDeque = { 1, 2, 3, 4, 5 };

    // Printing the original deque
    cout << "Original Deque: ";
    for (int num : myDeque) {
        cout << num << " ";
    }
    cout << endl;

    // Removing the element from the beginning of the deque
    myDeque.pop_front();

    // Printing the updated deque
    cout << "Deque After Removal: ";
    for (int num : myDeque) {
        cout << num << " ";
    }
    cout << endl;

    return 0;
}

Output

Original Deque: 1 2 3 4 5 
Deque After Removal: 2 3 4 5 

Time Complexity: O(1)
Auxiliary Space: O(1)