Functional Programming in C++

Functional programming isn’t just for Haskell or Lisp — many of its ideas have been part of C++ for years, and modern features like lambdas, std::function, ranges, and std::variant make those ideas easier to use than ever.

In this episode of 'The Curious Developer', Jesper Pedersen talks with Ivan Čukić about how to apply functional programming techniques in everyday C++ without switching languages. Ivan explains what “functional programming in C++” really means, how higher‑order functions show up in the standard algorithms, and how concepts like immutability and sum types can make code safer and easier to reason about.

You’ll learn:

• What functional programming is (in practical C++ terms)
• How higher‑order functions, predicates and lambdas already appear in standard algorithms
• How ranges let you write clear, pipeline‑style code over collections
• Why immutability and persistent/immutable data structures can be efficient in C++
• How to use std::variant and “states” to avoid invalid program states
• Where functional techniques fit alongside object‑oriented and generic programming in modern C++

Ivan also shares insights from his book, Functional Programming in C++, why its core ideas still apply as the language evolves, and why many “functional” techniques are simply examples of good, modern C++ design. This episode is ideal for developers who know some C++ and want to write clearer, safer code by borrowing proven ideas from the functional programming world—without leaving C++.

Links

• Functional Programming in C++
• KDAlgorithms (Jesper's algorithms library)
• Juan Pedro's talk on immutable data structures (Meeting C++ 2025)
• C++ Weekly With Jason Turner

Chapters

00:00 Welcome

01:39 About his book on functional programming

03:22 Why functional programming in C++?

04:15 What is functional programming

07:56 How does functional programming fit in with object oriented programming?

10:20 Immutable data

13:39 Example of functional programming

17:30 Performance

19:46 A more exotic example - sumtypes

27:30 Is C++ harder than Haskell for functional programming?

28:23 Wish: Pattern Matching

30:40 Switching on strings....

34:05 What is on the backside on your book.

All 'The Curious Developer' videos

About the guest

Dr Ivan Čukić is the author of "Functional Programming in C++" (Manning Publications), a KDAB and KDE developer, a C++ trainer and consultant as well as a Free/Libre Software enthusiast.