C++ Standard Library: Complete Overview and Examples

C++ Standard Library: Complete Overview

The C++ Standard Library is a powerful set of classes, functions, macros, and templates that comes with any C++ compiler. It provides ready-made solutions for most typical tasks: from working with data containers to networking and multithreading. In this article, we will break down the main components of the library, show code examples, and explain how to effectively use its capabilities.

Main Components of the Standard Library

The standard library is divided into several major sections:

• STL (Standard Template Library) — containers, iterators, algorithms, and function objects.
• Input/Output — streams (iostream), file streams (fstream), string streams (sstream).
• Strings — the std::string and std::string_view classes.
• Numeric Operations — mathematical functions (cmath), random numbers (random), complex numbers (complex).
• Multithreading — threads (thread), mutexes, condition variables.
• Utilities — std::optional, std::variant, std::any, smart pointers (shared_ptr, unique_ptr).

STL Containers

Containers are template classes designed for storing collections of objects. They are divided into sequential and associative containers.

Sequential Containers

• std::vector — dynamic array. Fast index access, slow insertion in the middle.
• std::deque — double-ended queue. Fast insertion/deletion at both ends.
• std::list — doubly linked list. Fast insertion/deletion anywhere, but slow index access.

#include <iostream>#include <vector>

int main() {    std::vector<int> numbers = {10, 20, 30, 40};    numbers.push_back(50); // Adding to the end    for (int n : numbers) {        std::cout << n << " ";    }    return 0;}

Associative Containers

• std::set — set of unique elements (sorted).
• std::map — key-value dictionary (sorted by key).
• std::unordered_set / std::unordered_map — hash tables (unsorted but faster).

#include <iostream>#include <map>

int main() {    std::map<std::string, int> ages;    ages["Alice"] = 30;    ages["Bob"] = 25;    for (const auto& [name, age] : ages) {        std::cout << name << ": " << age << std::endl;    }    return 0;}

Algorithms

The <algorithm> library contains over 100 algorithms for working with sequences: sorting, searching, copying, transformation, etc. All algorithms work through iterators, making them universal.

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

int main() {    std::vector<int> v = {5, 2, 8, 1, 9};    std::sort(v.begin(), v.end()); // Sorting in ascending order    auto it = std::find(v.begin(), v.end(), 8);    if (it != v.end()) {        std::cout << "Found: " << *it << std::endl;    }    return 0;}

Working with Strings

The std::string class provides convenient methods for working with text: searching, replacing, concatenation, comparison. In C++17, std::string_view was added for non-owning string views.

#include