List in C++ STL

Last Updated : 04 Oct, 2025

A list in C++ is a sequence container that allows you to store elements one after another.

Implemented as a doubly linked list and maintains both front and back for fast operations on both the ends.
Data is stored in non-contiguous memory, allowing fast insertion and deletion anywhere in the list (beginning, middle, or end).

C++

#include <iostream>
#include <list>
using namespace std;

int main()
{
    // Create a list of integers
    list<int> myList;

    // Add elements to the list
    myList.push_back(10);
    myList.push_back(20);
    myList.push_front(5);

    // Display elements
    cout << "List elements: ";
    for (int n : myList)
    {
        cout << n << " ";
    }
    cout << endl;

    return 0;
}

Output

List elements: 5 10 20

Syntax

A list is defined as the std::list class template inside the <list> header file.

list<T> l;

where,

T: Type of elements in the list.
l: Name assigned to the list.

Basic Operations

The basic operations of list are shown below:

1. Inserting Elements

insert() is used for fast insertion if the position iterator is known; otherwise, traverse the list to reach the position.
push_front() is used to insert at the beginning and push_back() to insert at the end.
Time complexity to insert element both at beginning and end : O(1).

C++

#include <iostream>
#include <list>
using namespace std;
int main()
{
    list<int> l = {3, 2};

    // Inserting an element at the end
    l.push_back(5);

    // Inserting an element at the beginning
    l.push_front(1);

    // Inserting an element at a specific position
    auto it = l.begin();
    advance(it, 2);
    l.insert(it, 4);

    for (auto i : l)
        cout << i << " ";
    return 0;
}

Output

1 3 4 2 5

2. Accessing Elements

Lists do not allow random access, so to get an element at a specific position, you need to go through the list one by one from the start or end.
The first and last elements can be accessed quickly using front() and back() methods.
Time complexity for accessing elements : O(n)

C++

#include <iostream>
#include <list>
using namespace std;

int main()
{
    list<int> l = {1, 3, 4, 2, 5};

    // Accessing first and last elements
    cout << l.front() << endl;
    cout << l.back() << endl;

    // Access third element
    cout << *next(l.begin(), 2);

    return 0;
}

Output

1
5
4

3. Updating Elements

List elements can be updated by accessing them with an iterator and using the assignment operator (=) to set a new value.
Since lists do not support random access, you must use an iterator to reach the element you want to update.\
Time complexity for updating: O(1) if you have the iterator, otherwise O(n) to reach the element.

C++

#include <iostream>
#include <list>
using namespace std;

int main()
{
    list<int> l = {1, 3, 4, 2, 5};

    // Changing the first element
    l.front() = 11;

    // Move iterator to the second element
    auto it = l.begin();
    advance(it, 2);

    // Update the value using iterator
    *it = 10;

    for (auto i : l)
        cout << i << " ";
    return 0;
}

Output

11 3 10 2 5

4. Finding Elements

To find an element in a list, you can use the find() function from the <algorithm> library.
find() returns an iterator to the element if it is found, or the end iterator if it is not found.
Time complexity for searching elements : O(n).

C++

#include <iostream>
#include <list>
using namespace std;

int main()
{
    list<int> l = {1, 3, 4, 2, 5};

    // Finding 4
    auto it = find(l.begin(), l.end(), 4);

    if (it != l.end())
        cout << *it;
    else
        cout << "Element Not Found!";
    return 0;
}

Output

5. Traversing

A list can be traversed using begin() and end() iterators in a loop.
Start from begin() and keep moving the iterator until it reaches end(), accessing each element along the way.
Time complexity for traversal : O(n).

C++

#include <iostream>
#include <list>
using namespace std;

int main()
{
    list<int> l = {1, 3, 4, 2, 5};

    // Traversing using iterators
    for (auto it = l.begin(); it != l.end(); ++it)
        cout << *it << " ";
        
    return 0;
}

Output

1 3 4 2 5

6. Deleting Elements

erase() deletes an element from the list using an iterator to its position.
pop_front() and pop_back() quickly delete the first and last elements of the list.
Time complexity for deletion : O(1)

C++

#include <iostream>
#include <list>
using namespace std;

int main()
{
    list<int> l = {1, 3, 4, 2, 5};

    // Deleting last element
    l.pop_back();

    // Deleting first element
    l.pop_front();

    // Deleting third element
    auto it = l.begin();
    advance(it, 2);
    l.erase(it);

    for (auto i : l)
        cout << i << " ";
    return 0;
}

Output

3 4

Other Member Functions of List

Following is the list of all member functions of std::list class in C++:

Functions	Description
size()	Returns the number of elements in the list.
empty()	Checks if the list is empty.
rbegin()	Returns a reverse iterator pointing to the last element of the list.
rend()	Returns a reverse iterator pointing to the element before the first element.
clear()	Removes all elements from the list.

List in C++ STL

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