C++ Set

🧺 C++ Set – Store Unique Values with Ease

A set in C++ is a special container that stores only unique elements, and keeps them in sorted order.

If you don’t want duplicates and need fast search, set is your hero! 🦸

🔧 Syntax to Declare a Set

#include <set>
using namespace std;

set<int> mySet;

🧪 Example: Insert and Display Elements

#include <iostream>
#include <set>
using namespace std;

int main() {
    set<int> numbers;

    numbers.insert(10);
    numbers.insert(5);
    numbers.insert(20);
    numbers.insert(10); // Duplicate, will be ignored

    for (int num : numbers) {
        cout << num << " ";
    }

    return 0;
}
  

🛠️ Useful Set Functions

• insert(value) – Add a new value (duplicates not allowed)
• erase(value) – Remove a value
• find(value) – Search for a value
• size() – Get total number of elements
• clear() – Remove all elements

🎯 Example: Search in Set

#include <iostream>
#include <set>
using namespace std;

int main() {
    set<int> ids = {1001, 1002, 1003};

    if (ids.find(1002) != ids.end()) {
        cout << "ID 1002 found!" << endl;
    } else {
        cout << "ID 1002 not found." << endl;
    }

    return 0;
}
  

✅ Summary

• set stores sorted, unique values only.
• Automatically ignores duplicates.
• Great when you need fast lookups without extra copies!