Uploaded January 2026 | Updated September 2026, 2 weeks ago
cppcon.org
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Using Floating-point in C++: What Works, What Breaks, and Why - Egor Suvorov - CppCon 2025
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Floating-point arithmetic is easy to write. But, when it goes wrong, it is much harder to debug. It's even harder to define what ""wrong"" means: a game has to be fast, but a financial report has to be reasonable for humans. This talk explores how different applications impose implicit requirements on floating-point behavior, what classical issues arise, how to work with them, and why there is sometimes no workaround.
We will start by looking at how floating-point operations are implemented in different C++ contexts, and the counter-intuitive implications that follow. We will see how different environments find subtly different balances between correctness, predictability, and performance. We will then examine code examples that produce subtly incorrect results or even UB, but are still easily fixable.
Next, we will dive into more complicated calculations and understand where we are restricted or helped by IEEE-754, C++, and computational mathematics. The talk will conclude with practical recommendations: how to define realistic expectations, how to test and structure your code, and how libraries can and/or cannot help you.
If you've ever been surprised by floating-point behavior in C++, this talk will tell you what's going on.
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Slides: github.com/CppCon/CppCon2025/blob/main/Presentations/Using_Floating-point.pdf
Work at Hudson River Trading (HRT): tinyurl.com/safxfctf
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Egor Suvorov
Egor Suvorov is a senior software engineer at Bloomberg, where he works on DataLayer, the company's real-time streaming data transformation pipeline. Previously, he led a freshman C++ course, where his students uncovered and reported dozens of bugs in various C++ tools. Egor was also part of the winning team of the ACM ICPC 2014 World Finals.
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CppCon is the annual, week-long face-to-face gathering for the entire C++ community. The conference is organized by the C++ community for the community. You will enjoy inspirational talks and a friendly atmosphere designed to help attendees learn from each other, meet interesting people, and generally have a stimulating experience. Taking place this year in Aurora, Colorado, near the Denver airport, and including multiple diverse tracks, the conference will appeal to anyone from C++ novices to experts.
Annual CppCon Conference - cppcon.org
linkedin.com/company/cppcon
https://x.com/cppcon
facebook.com/CppConference
reddit.com/r/cppcon
https://mastodon.social/@CppCon
---
Videos Filmed & Edited by Bash Films: BashFilms.com
YouTube Channel Managed by Digital Medium Ltd: events.digital-medium.co.uk
---
#cpp #cplusplus #programming #coding #softwareengineering
cppcon.org
---
Using Floating-point in C++: What Works, What Breaks, and Why - Egor Suvorov - CppCon 2025
---
Floating-point arithmetic is easy to write. But, when it goes wrong, it is much harder to debug. It's even harder to define what ""wrong"" means: a game has to be fast, but a financial report has to be reasonable for humans. This talk explores how different applications impose implicit requirements on floating-point behavior, what classical issues arise, how to work with them, and why there is sometimes no workaround.
We will start by looking at how floating-point operations are implemented in different C++ contexts, and the counter-intuitive implications that follow. We will see how different environments find subtly different balances between correctness, predictability, and performance. We will then examine code examples that produce subtly incorrect results or even UB, but are still easily fixable.
Next, we will dive into more complicated calculations and understand where we are restricted or helped by IEEE-754, C++, and computational mathematics. The talk will conclude with practical recommendations: how to define realistic expectations, how to test and structure your code, and how libraries can and/or cannot help you.
If you've ever been surprised by floating-point behavior in C++, this talk will tell you what's going on.
---
Slides: github.com/CppCon/CppCon2025/blob/main/Presentations/Using_Floating-point.pdf
Work at Hudson River Trading (HRT): tinyurl.com/safxfctf
---
Egor Suvorov
Egor Suvorov is a senior software engineer at Bloomberg, where he works on DataLayer, the company's real-time streaming data transformation pipeline. Previously, he led a freshman C++ course, where his students uncovered and reported dozens of bugs in various C++ tools. Egor was also part of the winning team of the ACM ICPC 2014 World Finals.
---
CppCon is the annual, week-long face-to-face gathering for the entire C++ community. The conference is organized by the C++ community for the community. You will enjoy inspirational talks and a friendly atmosphere designed to help attendees learn from each other, meet interesting people, and generally have a stimulating experience. Taking place this year in Aurora, Colorado, near the Denver airport, and including multiple diverse tracks, the conference will appeal to anyone from C++ novices to experts.
Annual CppCon Conference - cppcon.org
linkedin.com/company/cppcon
https://x.com/cppcon
facebook.com/CppConference
reddit.com/r/cppcon
https://mastodon.social/@CppCon
---
Videos Filmed & Edited by Bash Films: BashFilms.com
YouTube Channel Managed by Digital Medium Ltd: events.digital-medium.co.uk
---
#cpp #cplusplus #programming #coding #softwareengineering
