What functions or components complement the standard C++ library?

The C++ standard library (STL) includes containers, algorithms, iterators, and function objects. Additionally, there are extensions and components that enhance its functionality:

• Boost — a set of libraries that extend the capabilities of the standard library, including smart pointers, regular expressions, multithreading, and more.
• Qt — a framework for developing GUI and multithreaded applications, containing its own containers and utilities.
• Poco — libraries for network programming, file handling, threading, and others.
• STL Extensions — additional containers and algorithms not included in the standard.

Thus, the standard library is supplemented by third-party libraries and frameworks that expand the language's capabilities and simplify development.