List

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Sriparno08
Published Oct 31, 2024Updated May 12, 2025
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In C++, a list is a sequential container that stores elements in non-contiguous memory locations. It is included in the Standard Template Library (STL) and is implemented as a doubly linked list, allowing efficient insertion and deletion of elements at any known position with average constant time complexity. It is widely used in task scheduling systems, simulation engines, and real-time systems where deterministic performance is crucial.

Creating a List

In C++, a list is defined in the <list> header and is part of the std namespace:

#include <list>

std::list<data-type> name_of_list = {value1, value2, ...}

In the syntax:

  • data-type: Specifies the data type of the elements to be stored in the list (e.g., int, double, or user-defined data types).
  • name_of_list: The variable name for the list instance, used to reference and manipulate the list within the code.
  • value1, value2, ...: The values to be stored in the list.

Example

This example demonstrates the usage of lists in C++:

#include <iostream>
#include <list>


using namespace std;


int main() {
  // Create a list
  list<int> nums = {13, 24, 35, 46, 57, 68};


  // Print the elements of the list
  for(int num : nums) {
    cout << num << " ";
  }


  return 0;
}

Here is the output:

13 24 35 46 57 68

Adding Elements to a List

In C++, there are two methods to add elements to a list:

  • .push_front(): Adds the given element to the start of the list.
  • .push_back(): Adds the given element to the end of the list.

Here is the syntax for these methods:

list_name.push_front(element);
list_name.push_back(element);

Parameters:

  • element: The element to be added to the list.

Example

This example demonstrates the usage of the .push_front() and .push_back() methods in C++:

#include <iostream>
#include <list>


using namespace std;


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


  // Add elements to the list
  myList.push_front(5);
  myList.push_front(10);
  myList.push_back(15);
  myList.push_back(20);


  // Print the elements of the list
  for(int num : myList) {
    cout << num << " ";
  }


  return 0;
}

Here is the output:

10 5 15 20

Accessing Elements in a List

In C++, there are two methods to access elements in a list:

  • .front(): Returns the first element in the list.
  • .back(): Returns the last element in the list.

Here is the syntax for these methods:

list_name.front();
list_name.back();

Example

This example demonstrates the usage of the .front() and .back() methods in C++:

#include <iostream>
#include <list>


using namespace std;


int main() {
  // Create a list
  list<int> nums = {13, 24, 35, 46, 57, 68};


  // Display the first element in the list
  cout << " " << nums.front() << endl;


  // Display the last element in the list
  cout << " " << nums.back();


  return 0;
}

Here is the output:

13
68

Removing Elements from a List

In C++, there are three methods to remove elements from a list:

  • .pop_front(): Removes the starting element from the list.
  • .pop_back(): Removes the ending element from the list.
  • .remove(): Removes all occurrences of the given element from the list.

Here is the syntax for these methods:

list_name.pop_front();
list_name.pop_back();
list_name.remove(element);

Parameters:

  • element: The element to be deleted from the list.

Example

This example demonstrates the usage of the .pop_front(), .pop_back(), and .remove() methods in C++:

#include <iostream>
#include <list>


using namespace std;


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


  // Add elements to the list
  myList.push_front(5);
  myList.push_front(10);
  myList.push_back(15);
  myList.push_back(20);


  // Remove elements from the list
  myList.pop_front();
  myList.pop_back();
  myList.remove(5);




  // Print the elements of the list
  for(int num : myList) {
    cout << num << " ";
  }


  return 0;
}

Here is the output:

15

Iterating a List

In C++, the foreach loop can be used to iterate a list:

#include <iostream>
#include <list>


using namespace std;


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


  // Add elements to the list
  myList.push_front(15);
  myList.push_front(20);
  myList.push_back(25);
  myList.push_back(30);


  // Print the elements of the list
  for(int num : myList) {
    cout << num << " ";
  }


  return 0;
}

Here is the output:

20 15 25 30

Codebyte Example: Basic List Operations

This codebyte example performs some basic operations on a list:

Code
Output
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Frequently Asked Questions


1. Which is better, list or vector in C++?


It depends on your use case. Use std::list when you need frequent insertions/deletions in the middle of the sequence. Use std::vector for better performance when random access and contiguous memory are needed.


2. Is a list an array in C++?


No, a list is not an array in C++. A std::list is a doubly linked list, while an array is a contiguous block of memory. Their performance characteristics and use cases differ significantly.


3. What is the difference between an array and a list?


An array offers fast indexed access but resizing is costly. A list allows efficient insertions/deletions at any position but doesn’t support direct access to elements by index.


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