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C++ Day 39

  C++ Day 39 STL Containers (Deep Understanding & Real Usage) Till now, you already know arrays, vectors, loops, and STL algorithms. Today, we go one step deeper and understand STL containers , which are the backbone of modern C++ programming. In real projects and competitive coding, choice of container matters a lot. 1. What are STL Containers? STL containers are data structures provided by C++ to store data efficiently. They handle: memory management resizing element access performance optimization You focus on logic , not memory handling. 2. Categories of STL Containers STL containers are mainly divided into: Sequence Containers Associative Containers Unordered Containers Container Adapters 3. Sequence Containers These store data in sequence . 3.1 Vector Most used container in C++. vector< int > v; Key Features: Dynamic size Contiguous memory Fast random access Slower insertion in middle Example: v. push_...
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C++ Day 28

  Day 28: STL – Introduction to Standard Template Library

The Standard Template Library (STL) is one of the most powerful Characteristics in C++. it provides ready-to-use information structures and Procedures devising coding quicker and further efficient


🔹 topics to cover:

what is stl


Parts of stl:


containers


iterators


Procedures


types of containers:


sequence containers (vector number deque)


associative containers (set map)


unordered containers (unordered_set unordered_map)


container Adjustors (stack line up priority_queue)


📘 examples:

1. Using vector

cpp

Copy

Edit

#include 

#include 

using namespace std;


int main() {

    vector v = {1 2 3 4};


    v.Send_back(5); // Add element


    for (int i : v)

        cout << i << " ";  // Output: 1 2 3 4 5

}

2. exploitation set

cpp

copy

edit

#include 

#include 

using namespace std;


int main() {

    set s;

    sinsert(4);

    sinsert(2);

    sinsert(4); // parallel leave work neglected    for (int one : s)

        cout << one << " "; // output: ii 4

}

3. Using map

cpp

Copy

Edit

#include 

#include 

using namespace std;


int main() {

    map int=""> age;

    age["Alice"] = 30;

    age["Bob"] = 25;


    for (auto it : age)

        cout << it.first << ": " << it.second << endl;

}

🧪 practise Tasks:

Use vector to store and sort a list of integers.


Use set to store unique names from Operator input.


Use map to count the frequency of characters in a string.


Make a program that uses stack or queue.


✅ Goals for Today:

Understand the power of STL.


Be able to use basic STL containers: vector set map stack.


Use STL Procedures like sort() find().


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