What are some new features in C++20 with examples?

What are some new features in C++20 with examples?

C++20 introduced several exciting features! One notable feature is the 'concepts' which allows you to specify template requirements. For example:

template<typename T>
concept Integral = std::is_integral_v<T>;

template<Integral T>
T add(T a, T b) {
    return a + b;
}

Can you explain the 'ranges' feature?

Sure! The 'ranges' feature simplifies working with collections. Here's an example:

#include <ranges>
#include <vector>
#include <iostream>

int main() {
    std::vector<int> numbers = {1, 2, 3, 4, 5};
    auto even_numbers = numbers | std::views::filter([](int n) { return n % 2 == 0; });
    for (int n : even_numbers) {
        std::cout << n << ' ';
    }
}

What about the 'coroutines' feature?

Coroutines allow you to write asynchronous code more easily. Here's a simple example:

#include <coroutine>
#include <iostream>

struct Generator {
    struct promise_type {
        int current_value;
        auto get_return_object() { return Generator{}; }
        auto initial_suspend() { return std::suspend_always{}; }
        auto final_suspend() noexcept { return std::suspend_always{}; }
        void unhandled_exception() {}
        auto yield_value(int value) {
            current_value = value;
            return std::suspend_always{};
        }
    };
};

Generator generate() {
    for (int i = 0; i < 5; ++i) {
        co_yield i;
    }
}