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List in C++ STL

Last Updated : 19 Jan, 2026

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).

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.

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() andback()methods.

Output
1
5
4

Explanation: "next(l.begin(), 2)" moves the iterator two positions forward from the start of the list and * dereferences it to print the element at index 2 (the third element).

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.

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.

Output
4

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.

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.

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.

Forward List vs List

Feature

forward_list

list

Type of linked List

Singly linked list

Doubly linked list

Traversal

Can only traverse forward

Can traverse both forward and backward

Memory usage

Uses less memory (only one pointer per node)

Uses more memory (two pointers per node)

Insertion/Deletion

Fast insertion and deletion, but only at or after a given position

Fast insertion and deletion anywhere (before or after a position)

Functions supported

Limited compared to list (no size(), no reverse iterators)

More complete interface including size(), reverse(), bidirectional iterators.

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