How to Insert Elements into a Set Using Iterator in C++?

In C++, a set is a container provided by the Standard Template Library(STL) that stores unique elements of the same type in a sorted order. In this article, we will learn how to use an iterator to insert elements into a set in C++.

Example:

Input:
myVector = {10, 20, 30, 40, 50}

Output:
myVector = {10, 20, 30, 40, 50, 60, 70, 80}

Insert Elements into a Set Using Iterator in C++

In C++, the std::set contains the std::set::insert() member function that also accepts iterators denoting a range of elements to be inserted in the set. These iterators can belong to any data container such as vector, deque, and even another set.

C++ Program to Insert Elements into a Set Using Iterator

// C++ program to insert elements into a set using iterator
#include <iostream>
#include <set>
#include <vector>
using namespace std;
int main()
{
    // initialzie a set
    set<int> s = { 10, 20, 30, 40, 50 };
    // initialize a vector whose elements will be added into
    // the set
    vector<int> vec = { 60, 70, 80 };
    // Printing the elements of the set before insertion
    cout << "Before Insertion:";
    for (const auto& element : s) {
        cout << element << " ";
    }
    cout << endl;
    // Inserting elements into the set using iterators
    s.insert(vec.begin(), vec.end());
    // Printing the elements of the set after insertion
    cout << "After Insertion:";
    for (const auto& element : s) {
        cout << element << " ";
    }
    cout << endl;
    return 0;
}

Before Insertion:10 20 30 40 50 
After Insertion:10 20 30 40 50 60 70 80 

Time Complexity: O(M logN) where N is the number of elements in the set and M is the number of elements in the vector.
Auxilary Space: O(M)

Note: If you are looking for a method to insert element at a particular position in a set using iterator, it is not possible as set always store data in some order.