diff --git a/CPP20.md b/CPP20.md index 0134bfa..55ae236 100644 --- a/CPP20.md +++ b/CPP20.md @@ -34,6 +34,8 @@ C++20 includes the following new library features: - [std::bit_cast](#stdbit_cast) - [std::midpoint](#stdmidpoint) - [std::to_array](#stdto_array) +- [std::bind_front](#stdbind_front) +- [uniform container erasure](#uniform-container-erasure) ## C++20 Language Features @@ -611,6 +613,25 @@ int a[] = {1, 2, 3}; std::to_array(a); // returns `std::array` ``` +### std::bind_front +Binds the first N arguments (where N is the number of arguments after the given function to `std::bind_front`) to a given free function, lambda, or member function. +```c++ +const auto f = [](int a, int b, int c) { return a + b + c; }; +const auto g = std::bind_front(f, 1, 1); +g(1); // == 3 +``` + +### Uniform container erasure +Provides `std::erase` and/or `std::erase_if` for a variety of STL containers such as string, list, vector, map, etc. + +For erasing by value use `std::erase`, or to specify a predicate when to erase elements use `std::erase_if`. Both functions return the number of erased elements. + +```c++ +std::vector v{0, 1, 0, 2, 0, 3}; +std::erase(v, 0); // v == {1, 2, 3} +std::erase_if(v, [](int n) { return n == 0; }); // v == {1, 2, 3} +``` + ## Acknowledgements * [cppreference](http://en.cppreference.com/w/cpp) - especially useful for finding examples and documentation of new library features. * [C++ Rvalue References Explained](http://web.archive.org/web/20240324121501/http://thbecker.net/articles/rvalue_references/section_01.html) - a great introduction I used to understand rvalue references, perfect forwarding, and move semantics. diff --git a/README.md b/README.md index f9f4149..d4eb394 100644 --- a/README.md +++ b/README.md @@ -33,6 +33,8 @@ C++20 includes the following new library features: - [std::bit_cast](#stdbit_cast) - [std::midpoint](#stdmidpoint) - [std::to_array](#stdto_array) +- [std::bind_front](#stdbind_front) +- [uniform container erasure](#uniform-container-erasure) C++17 includes the following new language features: - [template argument deduction for class templates](#template-argument-deduction-for-class-templates) @@ -715,6 +717,25 @@ int a[] = {1, 2, 3}; std::to_array(a); // returns `std::array` ``` +### std::bind_front +Binds the first N arguments (where N is the number of arguments after the given function to `std::bind_front`) to a given free function, lambda, or member function. +```c++ +const auto f = [](int a, int b, int c) { return a + b + c; }; +const auto g = std::bind_front(f, 1, 1); +g(1); // == 3 +``` + +### Uniform container erasure +Provides `std::erase` and/or `std::erase_if` for a variety of STL containers such as string, list, vector, map, etc. + +For erasing by value use `std::erase`, or to specify a predicate when to erase elements use `std::erase_if`. Both functions return the number of erased elements. + +```c++ +std::vector v{0, 1, 0, 2, 0, 3}; +std::erase(v, 0); // v == {1, 2, 3} +std::erase_if(v, [](int n) { return n == 0; }); // v == {1, 2, 3} +``` + ## C++17 Language Features ### Template argument deduction for class templates