How to create an Empty Set in C++

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How to create an Empty Set in C++ ?

Answer

To create an empty set in C++, you can use the unordered_set container from the C++ Standard Template Library (STL).

✐ Examples

1 Create Empty Set using unordered_set

In this example,

We include the <unordered_set> header to access the unordered_set container from the C++ STL.
We declare an empty unordered_set named emptySet, specifying the type of elements it will hold.
The unordered_set container in C++ provides constant-time average complexity for operations like insertions, deletions, and lookups.

C++ Program

#include <iostream>
#include <unordered_set>

int main() {
    // Declare an empty set
    std::unordered_set<int> emptySet;

    // emptySet is now ready to be used as an empty set

    // Example usage:
    // Add elements to the set
    emptySet.insert(5);

    // Remove elements from the set
    emptySet.erase(5);

    // Check if an element is present in the set
    bool containsElement = (emptySet.find(5) != emptySet.end());

    std::cout << "Is element 5 present in the set: " << std::boolalpha << containsElement << std::endl;
    return 0;
}

Output

Is element 5 present in the set: false

Summary

In this tutorial, we learned How to create an Empty Set in C++ language with well detailed examples.