Appendix 2: Modern C++ Best Practices

In this appendix we briefly discuss the best practices of modern C++. Many of these ideas are distilled from Effective Modern C++ and the Google C++ Style Guide, as well as the C++ Core Guidelines maintained by Bjarne Stroustrup and Herb Sutter. The goal of this appendix is to summarize widely accepted practices that help ensure the overall quality of your code.

Common Tools

Good tooling catches a large class of problems before they ever reach production:

• Enable warnings, and treat them as errors. Compile with -Wall -Wextra (and consider -Wpedantic); -Werror keeps warnings from accumulating.
• Run sanitizers during testing. AddressSanitizer (-fsanitize=address), UndefinedBehaviorSanitizer (-fsanitize=undefined) and ThreadSanitizer (-fsanitize=thread) catch memory errors, undefined behavior, and data races at run time.
• Format and lint automatically. clang-format keeps style consistent, and clang-tidy flags bug-prone patterns and suggests modernizations.
• Use a modern build system and package manager, such as CMake together with vcpkg or Conan, to make builds reproducible.
• Experiment quickly with Compiler Explorer to inspect the generated assembly and compare compilers and standards.

Coding Style

A consistent style makes a codebase far easier to read and maintain:

• Pick a style guide and apply it consistently across the whole project; consistency matters more than the specific choices.
• Be const-correct: mark variables, member functions, and parameters const whenever they do not need to mutate state.
• Use auto to avoid redundant type spelling, but not at the cost of readability — keep the reader able to tell what a name means.
• Prefer the standard library (containers, algorithms, std::string) over hand-rolled equivalents.

Overall Performance

• Measure before you optimize. Use a profiler to find the real hot spots instead of guessing; premature optimization wastes effort and harms readability.
• Avoid unnecessary copies. Pass large objects by const&, or take by value and std::move when you need a copy anyway; reserve() containers when the final size is known.
• Let the compiler help. Return local objects by value and rely on (guaranteed) copy elision rather than returning via output parameters.
• Prefer move semantics for expensive-to-copy types, and remember that std::move is a cast, not an operation.

Code Security

• Manage resources with RAII. Wrap every resource (memory, files, locks, sockets) in an object whose destructor releases it.
• Prefer smart pointers (std::unique_ptr, std::shared_ptr) over raw new/delete; avoid owning raw pointers.
• Avoid undefined behavior: no out-of-bounds access, no signed overflow, no use-after-free, no strict-aliasing violations (see §9.5). Sanitizers help detect these.
• Prefer std::span, std::array, and .at() over raw pointers and unchecked indexing when bounds matter, and avoid C-style casts in favor of the named C++ casts.

Maintainability

• Keep functions small and focused on a single responsibility; prefer standard algorithms over hand-written loops to express intent clearly.
• Make interfaces hard to misuse: use strong types and enum classes instead of bare int/bool flags.
• Write tests, and run them continuously so regressions are caught early.
• Document why, not what: the code already says what it does.

Portability

• Use fixed-width integer types (std::int32_t, etc.) from <cstdint> when the exact size matters; do not assume int is 32 bits or that char is signed.
• Avoid implementation-defined and platform-specific behavior; when you must depend on it, isolate it behind a small abstraction.
• Prefer the standard library over platform-specific APIs (e.g. <filesystem>, <thread>, <chrono>) so the same code builds across platforms.
• When byte order matters, query it explicitly (std::endian in C++20) rather than assuming little- or big-endian.

Table of Content | Previous Chapter | Next Chapter: Modern C++ Feature Index

Licenses

This work was written by Ou Changkun and licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. The code of this repository is open sourced under the MIT license.