How to Initialize a Set in C++ - Step by Step Examples

How to Initialize a Set in C++ ?

Answer

To initialize a set in C++, you can use the std::set container from the C++ Standard Template Library (STL).


✐ Examples

1 Initialize Set with Elements

In this example,

  1. We include the necessary header <set> to access the std::set container from the C++ STL.
  2. We declare a std::set variable named mySet, specifying the type of elements it will hold.
  3. We initialize mySet by providing initial elements in the constructor.
  4. The std::set container in C++ maintains a sorted collection of unique elements.

C++ Program

#include <iostream>
#include <set>

int main() {
    // Declare and initialize a set
    std::set<int> mySet = {1, 2, 3};

    // mySet is now initialized with elements 1, 2, and 3

    // Example usage:
    // Add elements to the set (not applicable in std::set)
    // Remove elements from the set (not applicable in std::set)
    // Check if an element is present in the set
    bool containsElement = mySet.count(2) > 0;

    std::cout << "Is element 2 present in the set: " << std::boolalpha << containsElement << std::endl;
    return 0;
}

Output

Is element 2 present in the set: true

2 Initialize Empty Set

In this example,

  1. We include the necessary header <set> to access the std::set container from the C++ STL.
  2. We declare an empty std::set variable named emptySet, specifying the type of elements it will hold.
  3. We initialize emptySet using the default constructor std::set().
  4. The std::set container in C++ maintains a sorted collection of unique elements.

C++ Program

#include <iostream>
#include <set>

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

    // emptySet is now initialized 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.count(5) > 0;

    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 Initialize a Set in C++ language with well detailed examples.


More C++ Sets Tutorials

  1. How to create an Empty Set in C++ ?
  2. How to Initialize a Set in C++ ?
  3. How to Get Length of a Set in C++ ?
  4. How to create a Set of size N in C++ ?
  5. How to create a Set of Numbers from 1 to N in C++ ?
  6. How to create a Set of integers in C++ ?
  7. How to create a Set of Strings in C++ ?
  8. How to Access Items in a Set in C++ ?
  9. How to get a Random Item in a Set in C++ ?
  10. How to Iterate Over a Set in C++ ?
  11. How to check if a Set is Empty in C++ ?
  12. How to check if a Set is Not Empty in C++ ?
  13. How to get Subset from a Set in C++ ?
  14. How to check if a Specific Item is present in the Set in C++ ?
  15. How to check if a Set contains all the items of Another Set in C++ ?
  16. How to Sort Items of a Set in C++ ?
  17. How to Copy a Set in C++ ?
  18. How to add an Item to a Set in C++ ?
  19. How to find Union of Two Sets in C++ ?
  20. How to find Intersection of Two Sets in C++ ?
  21. How to check if Two Sets are Equal in C++ ?
  22. How to Convert a Set of Integers to a Set of Strings in C++ ?
  23. How to Convert a Set of Strings to a Set of Integers in C++ ?
  24. How to Convert a Set of Floats to a Set of Strings in C++ ?
  25. How to Filter Items of a Set based on a Condition in C++ ?
  26. How to Remove Specific Item from a Set in C++ ?
  27. How to Remove Items from Set based on a Condition in C++ ?
  28. How to create a Set of Sets in C++ ?