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.
CPP
// 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;
} |
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
Time Complexity – Linear O(N)