B.5 — Introduction to C++23

What is C++23?

In February of 2023, the ISO (International Organization for Standardization) approved a new version of C++, called C++23.

New improvements in C++23

For your interest, here’s a list of the major changes that C++23 adds. Note that this list is not comprehensive, but rather intended to highlight some of the key changes of interest.

Constexpr <cmath> (e.g. std::abs()), and <cstdlib> (6.7 -- Relational operators and floating point comparisons).
Constexpr std::unique_ptr (no lesson yet).
Explicit this parameter (no lesson yet).
Fixed-size floating point types (via <stdfloat>) (no lesson yet).
Formatted printing functions std::print and std::println (no lesson yet)
Literal suffixes for std::size_t and the corresponding signed type (5.2 -- Literals).
Multidimensional subscript operator[] (Mentioned in lesson 17.13 -- Multidimensional std::array).
Multidimensional span std::mdspan (17.13 -- Multidimensional std::array).
Preprocessor directives #elifdef and #elifndef (no lesson yet).
Preprocessor directive #warning (no lesson yet).
Stacktrace library (no lesson yet)
Standard library modules std (and std.compat) (no lesson yet).
Static operator() and operator[] (no lesson yet).
std::bitset now fully constexpr.
std::expected (no lesson yet)
std::ranges algorithms starts_with, ends_with, contains (no lesson yet)
std::string::contains and std::string_view::contains (no lesson yet)
std::to_underlying to get the underlying type of enum (13.6 -- Scoped enumerations (enum classes)).
std::unreachable() (no lesson yet).
Using unknown pointers and references in constant expressions (17.2 -- std::array length and indexing).