How to Replace Specific Element in Set in C++?

In C++ STL (Standard Template Library), a set is a container that stores unique elements in a sorted order. In this article, we will learn how to replace a specific element in a set in C++.

Example:

Input:
Initial Set: 10 20 30 
// Replace 20 with 25

Output:
Modified Set: 10 25 30

Replace Specific Element in a Set in C++

In C++, we can easily replace a specific element in a set by removing the old element using the std::set::erase() function and then insert the new element using the std::set::insert() function.

Syntax

set_name.erase(value_to_replace); // Erase the old element
set_name.insert(new_value); // Insert the new element

C++ Program to Replace Specific Element in a Set

Below is the Implementation of the above approach:

C++

// C++ program to replace the specific element in a set
#include <iostream>
#include <set>
using namespace std;

int main()
{
    // Create a set and insert elements
    set<int> mySet;
    mySet.insert(10);
    mySet.insert(20);
    mySet.insert(30);

    // Print the initial set
    cout << "Initial Set: ";
    for (auto value : mySet) {
        cout << value << " ";
    }
    cout << endl;

    // Replace 20 with 25
    mySet.erase(20); // Erase the old element
    mySet.insert(25); // Insert the new element

    // Print the modified set
    cout << "Modified Set: ";
    for (auto value : mySet) {
        cout << value << " ";
    }
    cout << endl;

    return 0;
}

// This code is contributed by Susobhan Akhuli

Output

Initial Set: 10 20 30 
Modified Set: 10 25 30 

Time Complexity: O(logN)
Space Complexity: O(1)

Note: The new element may not be placed in the same position as set elements are sorted in some order.