How to Add an Element to a Set in C++?

In C++ STL, a set is a container that stores unique elements in a sorted order. In this article, we will learn how to add an element to a set in C++ STL.

Example:

Input:
mySet = {1, 2, 4, 5, 8}
Element to add: 3

Output:
mySet = {1, 2, 3, 4, 5, 8}

Add an Element to a Set in C++

To add a specific element to a std::set in C++, we can use the std::set::insert() function. This function takes a value as an argument and inserts it into the set and maintains the set’s sorted order.

C++ Program to Add an Element to a Set

// CPP program to add an element to a Set
#include <iostream>
#include <set>
using namespace std;

// Driver Code
int main()
{
    set<int> mySet = { 1, 2, 4, 5, 6 };

    // Adding element 3 to the set using insert() function
    mySet.insert(3);

    // Displaying the elements of the set
    for (int elem : mySet) {
        cout << elem << " ";
    }
    return 0;
}

// This code is contributed by Susobhan Akhuli

1 2 3 4 5 6 

Time Complexity: O(log n), where n is the number of elements in the set.
Auxiliary Space: O(1)

We can also elements to the set by using the emplace() function.