The C++ language and its standards

The C++ language: purpose and history

C++ (pronounced “see plus plus”) is a general-purpose programming language with static typing. A type defines which values an object can store and which operations are allowed on it. The compiler checks a large part of these rules before the program runs. For example, you can multiply a number by another number, but the text name of a room is not a numeric length. Your code needs to express such differences.

Bjarne Stroustrup started working on C with Classes in 1979. He combined the ability to work close to the hardware, typical of C, with classes for describing complex systems. The name C++ appeared in 1983; in 1985 the first edition of the book The C++ Programming Language was published. The ++ sign in the language means incrementing a value by one. The history and the author’s materials are available at https://www.stroustrup.com/, and the evolution of the standards is shown in Fig. 1.1.

Figure 1.1. Milestones of C++ and its standards

C++ supports several ways of organizing a program. Procedural programming breaks a problem into functions; object-oriented programming combines data and operations into classes; generic programming lets you write algorithms for different types. That is why your first program can consist of just the main function: you don’t need to declare your own class for every console example. The course moves on to classes after you have mastered variables, functions, references, and memory management.

The language is used in system software, game engines, embedded devices, image processing, and high-performance computing. What these tasks have in common is the need to control memory and time costs. At the same time, speed doesn’t come automatically from the choice of language: a poor algorithm stays slow. Controlling resources takes discipline, checks, and the use of libraries.

Table 1.1. C++ compared with other languages

Language	A difference that matters at the start of learning
C	Shares its syntactic origins with C++, but is a separate language. Not every C program is a valid C++ program.
C++	A regular build produces machine code for the chosen platform. Object lifetime and resource ownership are part of the design.
C#	Applications often run on .NET with a garbage collector; ahead-of-time compilation with Native AOT also exists.
Java	The typical path involves bytecode and the JVM; syntactic similarity doesn’t mean the same memory rules or libraries.

Source code can be portable if it doesn’t depend on the specifics of the operating system. A finished Windows .exe file does not become a Linux application when you copy it: you need a suitable compiler, libraries, and a new build. The same code can also reveal errors on another compiler if it relied on a nonstandard extension. In this course, the main tested platform is Windows 11, Visual Studio 2026, and MSVC for x64.

Language standards and compiler support

A standard describes the rules of the language and the standard library. C++ is developed by the ISO/IEC JTC1/SC22/WG21 committee. A standard is not a program that you install: its rules are implemented by compilers and libraries. MSVC ships with Microsoft tools; GCC and Clang are other implementations. Their version numbers don’t match the year in the name of a C++ standard.

The first international standard was C++98; C++03 refined it. C++11 brought a major update of the language, and subsequent editions appear roughly every three years. Table 1.2 gives a brief overview. The name of a standard refers to an edition, not to the earliest date when all its features appeared in every product.

Table 1.2. Editions of the C++ standard

Edition	Example features
C++98/03	Classes, templates, standard library containers and algorithms.
C++11	auto, lambda expressions, move semantics, smart pointers.
C++14/17	Refinements of C++11, structured bindings, std::optional, filesystem paths.
C++20	Concepts, ranges, coroutines, modules, std::format.
C++23	std::print, std::println, std::expected, the std library module.
C++26	The next edition; the availability of each feature is checked against the implementation and the specific compiler version.

The course targets C++26, but this is not a promise that MSVC fully implements all of its features. At the time of checking, the standardization status page https://isocpp.org/std/status described C++26 as an edition in progress; we don’t assume a final ISO publication date here. Approval of the technical content, ISO publication, and the release of support in MSVC are different events. In particular, std::println belongs to C++23, even though it is used in our C++26 course. You don’t need to enable contracts or reflection for this topic.

The /std:c++latest switch selects newly implemented features, including features of the draft of the next standard. After a tools update, the contents of this mode may change. For reproducible work, record the Visual Studio version, the MSVC number from the cl output, and the build options. Microsoft publishes the conformance table here: https://learn.microsoft.com/cpp/overview/visual-cpp-language-conformance.

Standard and implementation

If the compiler doesn’t recognize a header or a construct, first check the toolset version and the selected standard. Changing C++23 to C++26 in a program’s message doesn’t add support for new features.

How source code becomes a program

A developer stores source code in a .cpp file. To run it, the text must be turned into machine instructions. A build consists of several stages that the IDE runs automatically (Fig. 1.2). It is important to tell them apart: a message about an unknown name and one about a missing function definition occur at different stages and have different causes.

Figure 1.2. From source files to an executable program

1. The preprocessor processes directives such as #include <print>. Headers provide declarations and other required parts of a library. This is not downloading a file from the internet at run time.
2. The compiler analyzes the resulting text, checks types, and creates an object file .obj. One .cpp file with the contents of its included headers after preprocessing forms a translation unit.
3. The linker combines the object files and the required libraries, resolves references between them, and creates the executable file .exe.
4. The operating system loads the executable file, and the startup code of the runtime environment calls the main function.

A .h or .hpp file usually contains declarations that several source files use. A header should not be treated as a separate program. For example, two .cpp files can include a common header and be compiled separately, after which their .obj files are combined. An error in one header can cause diagnostics in several translation units at once.

A regular native C++ program doesn’t need a JVM or CLR to execute machine code. However, it may need Windows dynamic libraries and the Visual C++ Runtime. So “machine code” doesn’t mean “a single file with no dependencies.” A Debug build is not used as a way to distribute a finished product; the installation requirements of a Release program are checked separately.