Iterators are used in the Standard Template Library to access elements in containers. They allow algorithms to be applied to different container types in a generic way. The STL achieves efficiency through templates, providing compile-time polymorphism that is often faster than traditional run-time polymorphism implemented in other libraries.

1. Many useful classes can be reused if they are very generic, such as the Standard Template
Library (STL). For example in the STL we have containers and iterators. What is the major
purpose of using iterators? Explain. (give a long detailed answer )
Solution
The Standard Template Library ( STL ) is a software library for the C++ programming
language that influenced many parts of theC++ Standard Library. It provides four components
called algorithms , containers , functional , and iterators . [1]
The STL provides a ready-made set of common classes for C++, such as containers and
associative arrays, that can be used with any built-in type and with any user-defined type that
supports some elementary operations (such as copying and assignment). STL algorithms are
independent of containers, which significantly reduces the complexity of the library.
The STL achieves its results through the use of templates. This approach provides compile-time
polymorphism that is often more efficient than traditional run-time polymorphism. Modern C++
compilers are tuned to minimize abstraction penalty arising from heavy use of the STL.