Introduction to Standard Template Library

The Standard Template Library (STL) is a powerful collection of classes and functions in C++ that provides reusable, generic algorithms, containers, and iterators. It’s an essential component of modern C++ programming and offers a wealth of functionality to simplify and enhance your code.

Key Components of STL:

1. Containers:
   Containers are objects that store collections of other objects. They provide a way to organize and manipulate data efficiently. STL provides several container classes, each with its unique characteristics:
   – Vector: Dynamic array that automatically adjusts its size.
   – List: Doubly linked list that allows for fast insertions and deletions anywhere in the list.
   – Deque: Double-ended queue that supports fast insertion and deletion at both ends.
   – Set: Collection of unique, sorted elements.
   – Map: Collection of key-value pairs, where each key is unique.
   – Stack: Container with Last-In-First-Out (LIFO) access.
   – Queue: Container with First-In-First-Out (FIFO) access.
2. Iterators:
   Iterators are objects that allow traversal through the elements of a container. They act as pointers and provide a uniform way to access the elements regardless of the underlying container implementation. There are different types of iterators:
   – Input iterators: Allow reading elements from a container.
   – Output iterators: Allow writing elements to a container.
   – Forward iterators: Support forward traversal.
   – Bidirectional iterators: Support bidirectional traversal (forward and backward).
   – Random access iterators: Support random access to elements (e.g., accessing elements by index).
3. Algorithms:
   Algorithms are functions that operate on containers through iterators. They perform various operations such as searching, sorting, modifying, and manipulating elements in containers. STL provides a wide range of algorithms for common tasks, including:
   – Sorting: Sort elements in a container.
   – Searching: Search for elements in a container.
   – Transforming: Modify elements in a container based on certain criteria.
   – Copying: Copy elements between containers.
   – Merging: Merge elements from multiple containers into one sorted container.
   And many more…

Types of Container

1. Simple
   – Pair
2. Sequence
   – Array
   – Vector
   – Deque
   – List
   – Forward list
3. Associative
   – Map
   – Multimap
   – Set
   – Multiset
4. Unordered
   – Unordered set
   – Unordered multiset
   – Unordered map
   – Unordered multimap
5. Adapter
   – Stack
   – Queue
   – Priority queue