set in c++

In C++, the `set` is a container class that stores a collection of unique elements in a specific order. It is part of the Standard Template Library (STL) and provides a way to efficiently store and access elements without duplicates.


To use the `set` container in C++, you need to include the `<set>` header file. Here's an example of how to create and use a set in C++:


```cpp

#include <iostream>

#include <set>


int main() {

    // Create a set of integers

    std::set<int> mySet;


    // Insert elements into the set

    mySet.insert(5);

    mySet.insert(2);

    mySet.insert(8);

    mySet.insert(2);  // Duplicate value, will be ignored


    // Iterate over the elements in the set

    for (const auto& element : mySet) {

        std::cout << element << " ";

    }

    std::cout << std::endl;


    // Check if an element exists in the set

    if (mySet.count(8) > 0) {

        std::cout << "Element 8 is present in the set." << std::endl;

    } else {

        std::cout << "Element 8 is not present in the set." << std::endl;

    }


    // Remove an element from the set

    mySet.erase(2);


    // Check the size of the set

    std::cout << "Size of the set: " << mySet.size() << std::endl;


    // Clear all elements from the set

    mySet.clear();


    // Check if the set is empty

    if (mySet.empty()) {

        std::cout << "The set is empty." << std::endl;

    } else {

        std::cout << "The set is not empty." << std::endl;

    }


    return 0;

}

```


In this example, we create a set `mySet` and insert some elements into it. Since sets store unique elements, the duplicate value `2` is ignored. We then iterate over the set and print its elements.


Next, we demonstrate how to check if a specific element exists in the set using the `count` function. We also remove an element using the `erase` function and check the size of the set using the `size` function.


Finally, we clear all the elements from the set using the `clear` function and check if the set is empty using the `empty` function.


Remember to compile and run the program to see the output.

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