The C++ Standard Template Library is part of the ANSI standard for the C++ language, and extends the built-in types with a variety of features. The two most important and the ones discussed here are:
Together these mechanisms make it possible for you to use all manner of supplied common containers, along with suitable algorithms for searching, sorting, and managing the objects stored within them. The standard implementations can also be used as a starting point for your own classes.
This allows you to be more efficient and produce more correct code, because you don’t have to reinvent the existing solutions. Careful design is a must, however, and you need to be sure that you are choosing the correct mix of STL components ...