Favourite C++ features
C++17
- Boost filesystem
- execution policy: parallel algorithm support for range-based for loops - potential for easily parallelsing existing code
- structured bindings
- clamp
- std::optional
[[maybe_unused]]
C++20
Concepts
- Concepts are a revolutionary approach for writing templates! They allow you to put constraints on template parameters that improve the readability of code, speed up compilation time, and give better error messages.
C++20 gives us language support (new keywords - requires, concept) and a set of predefined concepts from the Standard Library.
In other words, you can restrict template parameters with a “natural” and easy syntax. Before C++20, there were various ways to add such constraints. See my other post Simplify Code with if constexpr and Concepts in C++17/C++20 - C++ Stories.
https://www.cppstories.com/2021/concepts-intro/
template <typename T>
void print(const std::vector<T>& vec) {
for (size_t i = 0; auto& elem : vec)
std::cout << elem << (++i == vec.size() ? "n" : ", ");
}
void print2(const std::vector<auto>& vec) {
for (size_t i = 0; auto& elem : vec)
std::cout << elem << (++i == vec.size() ? "n" : ", ");
}
Ranges and views
The ranges library provides components for dealing with ranges of elements, including a variety of view adapters: immutable views of things; a nod to strongly typed, const languages like Haskell, composing syntax.
Coroutines
A new stackless threading model that also allows lazy evaluation of infinite sequences.
Misc
contains()to check if a key is present in an associate container, rather thancount()orfind()which always search the whole container- spaceship operator
- range based for loops with initialiser
- bit header
- https://en.cppreference.com/w/cpp/utility/source_location
- https://en.cppreference.com/w/cpp/numeric/constants
Wish list
See the compiler support matrix.
std::format- modules - wait for clang12, gcc11
Modules
Look interesting but not available until clang-12.