Enumerators and collections class-CComEnumOnSTL

Introduction

C++, or "C with Classes," is a high-level, general-purpose programming language. Danish computer scientist Bjarne Stroustrup developed it to expand the C programming language. It is nearly always written as compiled code. Let's now discuss the enumerators and collections in the class CComEnumOnSTL in C++. 

Library

The language has significantly evolved, and current C++ has object-oriented, generic, functional, and low-level memory management capabilities. 

The C++ Standard Library is divided into two sections:

• Standard Function Library − This library contains functions that are not part of any class.
• Object-Oriented Class Library is a set of classes and functions that go with them.

Standard Function Library

The standard function library is organized into categories: 

• Time,
• date, 
• localization, 
• I/O, 
• Mathematical, 
• Wide-character functions, 
• Dynamic allocation 
• string and character handling

Object-Oriented Class Library

The Standard C++ Object-Oriented Library includes an extensive range of classes that serve a variety of everyday tasks, such as:

• I/O, strings, and arithmetic computation. 
• Library inclusive of The Numeric Classes, 
• The String Class, 
• The Standard C++ I/O Classes, 
• The STL Allocators, 
• The STL Algorithms, 
• The Localization library, 
• The STL Function Objects, 
• Exception Handling Classes, 
• The STL Container Classes, 
• The STL Iterators, 
• Miscellaneous Support Library

Technically, there's no "STL"; there's just the standard C++ library. The ATL classes were named before the C++ standard was finalized, so they still use the old "STL" name.

Enumerators and Collections classes

A user-defined type called an enumeration consists of a collection of named integral constants, sometimes referred to as enumerators. A collection class serves as a container class for one or more elements of a certain kind.

The following classes support COM collections and enumerations:

• CComEnumOnSTL is CComEnum defines an object based on an array.
• CComEnumImpl implements items being enumerated that are stored in an array.
• IEnumOnSTLImpl implements a COM enumerator interface where the items being enumerated are stored in a C++ Standard Library-compatible container.
• ICollectionOnSTLImpl implements the collection interface's Count, Item, and _NewEnum properties.