How to Delete an Element from a Set in C++?

A set in C++ is a container that stores unique elements in a sorted order. In this article, we will learn how to delete a specific element from a set.

Example:

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

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

Delete an Element from a Set in C++

To delete a specific element from a std::set in C++, we can use the std::set::erase() function. This function removes all elements with a certain value from the set. We can also pass it to the iterator if we need.

C++ Program to Delete an Element from a Set in C++

C++

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

// Driver Code
int main()
{
    // Creating a set
    set<int> mySet = { 1, 2, 3, 4, 5 };

    // Printing elements before deletion
    cout << "Elements before deletion: ";
    for (int elem : mySet) {
        cout << elem << " ";
    }
    cout << endl;

    // Deleting element using iterators
    auto it = mySet.find(3);
    if (it != mySet.end()) {
        mySet.erase(it);
    }

    // Printing elements after deletion
    cout << "Elements after deletion using iterators: ";
    for (int elem : mySet) {
        cout << elem << " ";
    }
    cout << endl;

    return 0;
}

// This code is contributed by Susobhan Akhuli

Output

Elements before deletion: 1 2 3 4 5 
Elements after deletion using iterators: 1 2 4 5 

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