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Preface

The Evolution of C++: from classical to modern

Since its inception as "C with classes", C++ has experienced numerous significant revisions and improvements. The language is now standardized by ISO JTC1/SC22/WG21, a working group composed of C++ experts from various countries. The first standardized version of C++ was ISO/IEC 14882:1998, commonly known as C++98. The next edition, ISO/IEC 14882:2003, was a minor revision that addressed issues found in C++98.

The true revolution of C++ arrived with ISO/IEC 14882:2011, also known as C++11 or C++0x. Officially released in 2011, it had been delayed longer than originally planned, leading developers to joke about the delay by dubbing it C++0B, with the hexadecimal B representing the release year. C++11 is considered a watershed moment in the language's evolution, marking the transition from classical to modern C++. It introduced many important additions to both the core language and the standard library, including rvalue references/move semantics, auto type deduction, uniform initialization syntax using {} lists, lambdas, variadic templates, SFINAE rules, and various smart pointer classes, among other valuable features for crafting robust C++ programs.

A small extension to C++11 was introduced in ISO/IEC 14882:2014. This was followed by another major revision ISO/IEC 14882:2017, which added notable features like std::any, std::variant, and std::optional classes to the standard library.

C++20, i.e., ISO/IEC 14882:2020 was officially published on 15 December 2020, representing the latest major revision. The most welcomed core language features of C++20 include concepts for generic type constraints, modules for improved expression of program physical modules, and coroutines for non-preemptive multitasking. Among the many new standard library features, the ranges library is particularly exciting, as it enables functional programming with "pipeable" functions similar to F#, my favorite .NET language.

Given the impact and changes brought about by C++11/14/17/20, it's clear that pre-2011 C++ and post-2011 C++ are fundamentally different languages. This distinction is reflected in the terms "Classical C++" represented by C++98 and "Modern C++" represented by C++11 and later. Learning the reimagined modern C++ as a new language is necessary, whether it's approached with enthusiasm or apprehension.

C++ was designed with backward compatibility to C, allowing developers to use C-style programming constructs such as raw pointers, arrays, and null-terminated strings. As C++ has evolved, the focus has shifted towards reducing the reliance on C-style idioms and sticking to the "zero overhead" principle. Modern C++ is simpler, safer, more elegant, and retains its speed.

Who this book is for

This book expects readers to have a basic knowledge of C++ and a genuine interest in evolving their skills in modern C++. Most chapters are beginner-friendly, while some need extra focus. Advanced meta-template programming topics may require multiple readings but can be skipped initially. Beginners should refer to other C++ books for fundamental guidance.

What this book covers

This book focuses on helping readers learn and understand new C++11 to C++20 features. Where necessary, it also explains how new features are implemented in compilers.