Abstract:

This video announces a significant change in C++ programming, particularly regarding the "Hello World" standard output and general logging. The speaker highlights the historical complexity of std::cout with bit-shift operators, which initially deterred him from the language. With C++23, a new approach is introduced: std::print and std::println, which offer a simpler, more intuitive syntax similar to other programming languages. This new functionality is built upon std::format (introduced in C++20), a powerful string formatting utility inspired by the widely-used FMT library. The video details how std::format allows for flexible string composition with type inference and explains the process of integrating custom types for formatting. While C++23 adoption is still in its early stages (e.g., as a preview feature in Visual Studio), the speaker emphasizes that std::format alone provides a major improvement to C++ logging and output, paving the way for more user-friendly development practices.

Summarizing "Goodbye std::cout, Hello std::print"

• 0:02 A Major C++ Change: The video announces a significant shift in how "Hello World" is written in C++, moving away from the complex std::cout with bit-shift operators.
• 0:09 Speaker's Past Aversion: The speaker recounts how the unintuitive std::cout syntax (e.g., std::cout << "Hello") initially put him off C++ in his youth, leading him to prefer Java until he started working at EA.
• 1:32 C++23 Introduces std::print and std::println: Starting with C++23, programmers can use std::println (and std::print) for simpler output, resembling print functions in languages like Java or C#.
• 1:40 Compiler Adoption Status: As of June 2025, Visual Studio still lists C++23 features (like std::print) as "preview features" from the latest working draft, indicating early adoption.
• 5:42 std::format (C++20) - The Backbone: The new print functionality is built upon std::format, introduced in C++20, which allows for user-friendly string formatting using curly brackets {} for placeholders and type inference.
• 7:10 std::format Origin - The FMT Library: std::format is derived from the popular, long-standing third-party FMT formatting library, proposed by its author for inclusion in the C++ standard.
• 7:51 Impact on Logging: std::format has already begun replacing third-party logging libraries like SpeedLog in projects (e.g., Hazel game engine), streamlining logging by integrating formatting directly into the C++ standard library.
• 9:09 std::print vs. std::println: std::println automatically adds a newline character, whereas std::print does not. A std::println() call with no arguments (for a blank line) is slated for C++26.
• 10:50 Custom Type Formatting: The video demonstrates how to enable std::format and std::print to work with custom user-defined types (e.g., a Point struct) by specializing the std::formatter template.
• 12:23 Improved C++ Logging/Formatting: The speaker asserts that C++ now effectively has a built-in logging/formatting library, significantly enhancing developer experience, even if std::format (C++20) is a bigger deal than std::print (C++23) for existing projects.
• 13:46 Recommendation for New Projects: The speaker plans to use C++23's std::print functions for all new projects going forward.
• 3:48 Sponsor Highlight: Codeex, a project management tool designed for game developers, is introduced as the video's sponsor.