In C++, a set is a container class template from the Standard Template Library (STL) that stores unique elements in a sorted order.

A set stores only unique elements and does not allow duplicates. Each element in a set is sorted according to their comparison operator, which is by default the less-than operator.

Sets are implemented as binary search trees, which provides efficient insertion, deletion, and searching of elements. They have a time complexity of O(log n) for these operations.

Sets are useful in situations where you need to store unique elements in a sorted order. For example, you could use a set to store a list of unique employee IDs in a company. The set would automatically sort the IDs and remove any duplicates.

You can also use a set to implement various algorithms such as finding the intersection, union, or difference of two sets. The set container provides a set of member functions to perform these operations.

`#include <iostream> #include <set> using namespace std; int main() { // Create a set of integer values set<int> mySet; // Insert elements in the set mySet.insert(10); mySet.insert(20); mySet.insert(30); mySet.insert(40); mySet.insert(50); // Print the elements in the set cout << "Current set elements: " << endl; for (auto it = mySet.begin(); it != mySet.end(); it++) { cout << *it << endl; } cout << endl; // Search for an element in the set auto it = mySet.find(30); if (it != mySet.end()) { cout << "Element found in the set: " << *it << endl; } else { cout << "Element not found in the set" << endl; } // Erase an element from the set mySet.erase(40); // Print the modified set cout << "Modified set after erasing 40: " << endl; for (auto it = mySet.begin(); it != mySet.end(); it++) { cout << *it << endl; } cout << endl; // Clear all of the elements of the set mySet.clear(); // Check if the set is empty if (mySet.empty()) { cout << "Set is empty" << endl; } else { cout << "Set is not empty" << endl; } return 0; }`

This implementation creates an empty set of integer values

`mySet`

. It then adds elements to the set using the `insert()`

function. The elements are printed to the console using a for loop and the `begin()`

and `end()`

functions of the set.The

`find()`

function is used to search for an element in the set. If the element is found, its value is printed to the console.The

`erase()`

function removes an element from the set. The modified set is printed to the console.The

`clear()`

function deletes all of the elements of the set, and the `empty()`

function checks if the set is empty. Finally, the program returns 0.**PRACTICE PROBLEMS :**