特性

C++23 有什么新特性

...etc

...etc

C++11 features

C++11 feels like a new language -- stroustrup

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C++11 introduced a bewildering number of language features, including:

memory model - an efficient low level-model of modern hardware as a foundation for concurrency
auto and decltype - avoiding redundant repetition of type names
range-for - simple linear traversal of ranges
move semantics and rvalue references - minimizing copying of data
uniform initialization - an (almost) completely general syntax and semantics for initializing objects of all kinds and types
nullptr - a name for the null pointer
constexpr functions - compile-time evaluated functions
user-defined literals - literals for user-defined types
raw string literals - literals where escape characters are not needed, mostly for regular expressions
attributes - associating essentially arbitrary information with a name
lambdas - unnamed function objects
variadic templates - templates that can handle an arbitrary number of arguments of arbitrary types
template aliases - the ability to rename a template and to bind some template arguments for the new name
noexcept - a way of ensuring that an exception isn’t thrown from a function
override and final - explicit syntax for managing large class hierarchies
static_assert - compile-time assertions
long long - a longer integer type
default member initializers - give a data member a default value that can be superseded by initialization in a constructor
enum classes - strongly typed enumerations with scoped enumerators

And here is a list of the major standard-library components:

unique_ptr and shared_ptr - resource-management pointers relying on RAII
memory model and atomic variables
thread, mutex, condition_variable, etc. - type-safe and portable support for basic system- level concurrency
future, promise, and packaged_task, etc. - slightly higher-level concurrency
tuple - unnamed simple composite types
type traits - testable properties of types for use in metaprogramming
regular expression matching
random numbers - with many generators (engines) and distributions
Time - time_point and duration
unordered_map, etc. - hash tables
forward_list - a singly-linked list
array - a fixed-constant-sized array that knows its size
emplace operations - construct objects right within a container to avoid copying
exception_ptr - enables transfer of exceptions between threads

C++17 features

C++17 had about 21 new language features (depending on how you count), including:

Constructor template argument deduction - simplify object definitions
Deduction guides - an explicit notation for resolving constructor template argument deduction ambiguities
Structured bindings - simplify notation and eliminate a source of uninitialized variables
inline variables - simplify the use of statically allocated variables in header-only libraries
Fold expressions - simplify some uses of variadic templates
Explicit test in conditions - a bit like conditions in for-statements
Guaranteed copy elision - eliminate many redundant copy operations
Stricter expression evaluation order - prevents some subtle order-of-evaluation mistakes
auto as a template argument type - type deduction for value template arguments
Standard attributes to catch common mistakes - [[maybe_unused]], [[nodiscard]], and [[fallthrough]]
Hexadecimal floating-point literals
Constant expression if - simplify compile-time evaluated code

The C++17 standard-library added about 13 new features plus many minor modifications:

optional, variant, and any - standard-library types for expressing alternatives
shared_mutex and shared_lock (reader-writer locks) and scoped_lock
parallel STL - multi-threaded and/or vectorized versions of standard-library algorithms
file system - the ability to portably manipulate file-system paths and directories
string_view - a non-owning reference to an immutable sequence of characters
Mathematical special functions - including Laguerre and Legendre polynomials, beta func- tions, Riemann zeta function