Standard Template Library (extended)

• A C++ library providing generic, reusable data structures and algorithms
• Containers: vector (dynamic array), list (doubly linked list), map (key-value pairs, typically balanced-tree based), set (unique sorted elements), stack, queue
• Iterators: generalized pointers used to traverse container elements uniformly
• Algorithms: pre-built functions (e.g., sort(), find(), count()) that operate generically over containers via iterators

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Worked Example — vector, iterator, and sort() together

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
    vector<int> nums = {5, 2, 8, 1, 9};

    sort(nums.begin(), nums.end());   // algorithm operating via iterators

    for (auto it = nums.begin(); it != nums.end(); ++it)   // iterator traversal
        cout << *it << " ";

    cout << endl;
    return 0;
}

Output: 1 2 5 8 9

When to use which container (quick reference)

Self-Test Questions

1. What does an iterator generalize, and why is that useful for writing algorithms like sort()?
2. When would list be preferred over vector?