What actually is C++ STL (Standard Template Library)?

Answer 1

The STL is the Standard Template Library. It is a subset of the C++ standard library.

The STL provides generic implementations of useful algorithms and containers.

The containers provide any easy method of storing data in the program and then finding, sorting and performing other computations on that data.

Answer 2

the stl provides several useful functions in the c++ language.
eg - you can create dynamic arrays with vectors