C++ STL (Standard Template Library)

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* STL is a part of the C++ Standard Library and is sometimes referred to as the "heart of C++."

Standard Template Library

STL stands for the Standard Template Library in C++. It is a powerful set of C++ template classes to provide general-purpose classes and functions with templates that implement many popular and commonly used algorithms and data structures like vectors, lists, queues, and stacks.

The STL is designed to provide a set of reusable, generic templates, implemented using C++ templates, that implement many popular and commonly used algorithms and data structures. Key components of the STL include:

1. Containers: Containers are used to store and manage collections of objects. Examples include vectors, lists, queues, and maps.

2. Algorithms: Algorithms are a collection of functions that perform operations on sequences, such as searching, sorting, and transforming elements.

3. Iterators: Iterators provide a way to access the elements of a container sequentially. They act as a generalization of pointers.

4. Function Objects (Functors): Functors are objects that can be treated as though they are a function or function pointer. They are often used as arguments to algorithms.

The use of templates in the STL allows for generic programming, meaning that algorithms and data structures can be written in a way that is independent of the specific data types they operate on. This makes the STL highly flexible and versatile.

Here's a simple example of using the STL to create a vector, add elements to it, and sort it:

cpp Copy Code

#include＜iostream＞
#include＜vector>
#include＜algorithm>

int main() {
    // Create a vector of integers
    std::vector numbers = {5, 2, 8, 1, 3};

    // Add an element to the vector
    numbers.push_back(7);

    // Sort the vector
    std::sort(numbers.begin(), numbers.end());

    // Print the sorted vector
    for (int num : numbers) {
        std::cout << num << " ";
    }

    return 0;
}

Output:

1 2 3 5 7 8

* This program demonstrates the use of the vector container and the sort algorithm from the STL. The STL provides a high level of abstraction, making it easier to write efficient and reusable code.

Components of the STL:

The Standard Template Library (STL) in C++ provides a collection of template classes and functions that implement common data structures and algorithms. Here are some of the common components of the STL:

1. Containers:

• Vector ('std::vector'): Dynamic array that automatically resizes.

• List ('std::list'): Doubly-linked list.

• Deque ('std::deque'): Double-ended queue.

• Queue ('std::queue'): FIFO (First-In, First-Out) queue.

• Stack ('std::stack'): LIFO (Last-In, First-Out) stack.

• Set ('std::set'): Collection of unique, ordered elements.

• Map ('std::map'): Collection of key-value pairs.

• Unordered Set ('std::unordered_set'): Collection of unique, unordered elements.

• Unordered Map ('std::unordered_map'): Collection of key-value pairs with unordered keys.

2. Containers:

• Iterator ('iterator'): Generalized iterator interface for traversing elements in a container.

• Begin ('begin()'): Returns an iterator pointing to the first element.

• End ('end()'): Returns an iterator pointing one past the last element.

• Advance ('advance()'): Moves an iterator forward by a specified number of positions.

• Distance ('distance()'): Computes the distance between two iterators.

3. Algorithms:

• Sort ('std::sort'): Sorts elements in a range.

• Find ('std::find'): Finds the first occurrence of a value in a range.

• Transform ('std::transform'): Applies a function to each element in a range.

• Reverse ('std::reverse'): Reverses the order of elements in a range.

• Remove ('std::remove'): Removes elements from a range based on a value.

• Unique ('std::unique'): Removes consecutive duplicate elements from a range.

4. Utilities:

• Pair ('std::pair'): Stores two elements together as a single unit.

• Tuple ('std::tuple'): Stores multiple elements together as a single unit.

• Function ('std::function'): Wrapper for callable objects, providing a polymorphic function object.

5. Memory Management:

• Smart Pointers ('std::shared_ptr', 'std::unique_ptr', 'std::weak_ptr'): Smart pointers for automatic memory management.

• Allocators ('std::allocator'): Custom memory allocators.

5. Numeric Algorithms:

• Accumulate ('std::accumulate'): Computes the sum of elements in a range.

• Inner Product ('std::inner_product'): Computes the inner product of two ranges.

• Partial Sum ('std::partial_sum'): Computes partial sums of elements in a range.

Note: These are just a few examples of the many components provided by the STL, and It is an integral part of modern C++ programming.

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C++ STL

Concept of Standard Template Library in C++.