Modern C++
Programming
20. Containers, Iterators,
Ranges, and Algorithms
Federico Busato
2026-01-06
Table of Contents
1 Containers and Iterators
Semantic
2 Sequence Containers
std::array
std::vector
std::deque
std::list
std::forward_list
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Table of Contents
3 Associative Containers
std::set
std::map
std::multiset
4 Container Adaptors
std::stack, std::queue, std::priority_queue
5 Implement a Custom Iterator
Implement a Simple Iterator
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Table of Contents
6 Iterator Notes
7 Iterator Utility Methods
std::advance, std::next
std::prev, std::distance
Container Access Methods
Iterator Traits
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Table of Contents
8 Algorithms Library
std::find_if, std::sort
std::accumulate, std::generate, std::remove_if
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Table of Contents
9 C++20 Ranges
Key Concepts
Range View
Range Adaptor
Range Factory
Range Algorithms
Range Actions
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Containers and
Iterators
Containers and Iterators
Container
A container is a class, a data structure, or an abstract data type, whose instances
are collections of other objects
• Containers store objects following specific access rules
Iterator
An iterator is an object allowing to traverse a container
• Iterators are a generalization of pointers
• A pointer is the simplest iterator, and it supports all its operations
C++ Standard Template Library (STL) is strongly based on containers and
iterators
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Reasons to use Standard Containers
• STL containers eliminate redundancy, and save time avoiding writing your own
code (productivity)
• STL containers are implemented correctly, and they do not need to spend time to
debug (reliability)
• STL containers are well-implemented and fast
• STL containers do not require external libraries
• STL containers share common interfaces, making it simple to utilize different
containers without looking up member function definitions
• STL containers are well-documented and easily understood by other developers,
improving the understandability and maintainability
• STL containers are thread safe. Sharing objects across threads preserve the
consistency of the container
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Container Properties
C++ Standard Template Library (STL) Containers have the following properties:
• Default constructor
• Destructor
• Copy constructor and assignment (deep copy)
• Iterator methods begin() , end()
• Support std::swap
• Content-based and order equality ( ==, != )
• Lexicographic order comparison ( >, >=, <, <= )
• size()
∗
, empty() , and max_size() methods
∗
except for std::forward_list
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Iterator Concept
STL containers provide the following methods to get iterator objects:
• begin() returns an iterator pointing to the first element
• end() returns an iterator pointing to the end of the container (i.e. the element after the
last element)
There are different categories of iterators and each of them supports a subset of the
following operations:
Operation Example
Read *it
Write *it =
Increment it++
Decrement it–
Comparison it1 < it2
Random access it + 4 , it[2]
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