The C++ language, actually, contains some statements only and not any built-in functions. The C++ language does not, within the actual definition of the language, provide any method of performing I/O operations. Therefore, various functions (that are not part of the basic C++ language) that help perform I/O operations and some other operations that can't be directly performed using C++ basic statements, are stored together in form of a library. These stored functions can be called and used for the desired operations.
In computer science, a library is a collection of sub-programs used to develop other programs and software. Libraries are not independent programs rather they are helper code used in other independent programs.
The C++ library functions stores functions of same category (e.g., mathematical functions, string functions etc.) under separate files known as header files.
You will learn this chapter into the following three tutorials:
You will learn about C++ Header Files in the next tutorial.