Modern C++ Guidelines

C++ has accumulated four decades of features. Some of them are bad ideas the language can't remove without breaking existing code: raw new/delete, unscoped enums, C-style casts, macros for almost everything. Modern C++ has cleaner replacements for nearly all of them, and a written set of recommendations called the C++ Core Guidelines spells out which to prefer. This chapter walks through the most important guidelines: prefer auto, prefer ranges and algorithms over raw loops, prefer smart pointers over new/delete, use RAII everywhere, prefer scoped enums, keep const correctness, avoid macros, use override and final, follow the rule of zero, use std::string and std::string_view, use std::optional and std::variant for results, and prefer initializer lists. The chapter closes with the Guidelines Support Library (GSL) and the static-analysis tools that automate enforcement.