list insert() in C++ STL

The list::insert() is used to insert the elements at any position of list. This function takes 3 elements, position, number of elements to insert and value to insert. If not mentioned, number of elements is default set to 1.

Syntax:

insert(pos_iter, ele_num, ele)

Parameters: This function takes in three parameters:



  • pos_iter: Position in the container where the new elements are inserted.
  • ele_num: Number of elements to insert. Each element is initialized to a copy of val.
  • ele: Value to be copied (or moved) to the inserted elements.

Return Value: This function returns an iterator that points to the first of the newly inserted elements.

filter_none

edit
close

play_arrow

link
brightness_4
code

// C++ code to demonstrate the working of
// insert() function
  
#include <iostream>
#include <list> // for list operations
using namespace std;
  
int main()
{
    // declaring list
    list<int> list1;
  
    // using assign() to insert multiple numbers
    // creates 3 occurrences of "2"
    list1.assign(3, 2);
  
    // initializing list iterator to beginning
    list<int>::iterator it = list1.begin();
  
    // iterator to point to 3rd position
    advance(it, 2);
  
    // using insert to insert 1 element at the 3rd position
    // inserts 5 at 3rd position
    list1.insert(it, 5);
  
    // Printing the new list
    cout << "The list after inserting"
         << " 1 element using insert() is : ";
    for (list<int>::iterator i = list1.begin();
         i != list1.end();
         i++)
        cout << *i << " ";
  
    cout << endl;
  
    // using insert to insert
    // 2 element at the 4th position
    // inserts 2 occurrences
    // of 7 at 4th position
    list1.insert(it, 2, 7);
  
    // Printing the new list
    cout << "The list after inserting"
         << " multiple elements "
         << "using insert() is : ";
  
    for (list<int>::iterator i = list1.begin();
         i != list1.end();
         i++)
        cout << *i << " ";
  
    cout << endl;
}

chevron_right


Output:

The list after inserting 1 element using insert() is : 2 2 5 2 
The list after inserting multiple elements using insert() is : 2 2 5 7 7 2


My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.




Article Tags :
Practice Tags :


4


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.