Standard Template Library (STL)

        // Vector - Dynamic Array
vector<int> vec = {1, 2, 3};
vec.push_back(4);

// List - Doubly Linked List
list<string> lst = {"apple", "banana"};
lst.push_front("orange");

// Map - Key-Value Pairs
map<string, int> ages;
ages["Alice"] = 25;
ages["Bob"] = 30;
      

        vector<int> nums = {3, 1, 4, 1, 5, 9};

// Sorting
sort(nums.begin(), nums.end());

// Finding elements
auto it = find(nums.begin(), nums.end(), 4);

// Counting elements
int count = count_if(nums.begin(), nums.end(),
    [](int n) { return n > 3; });