Modern C++ guide

Introduction

I recently dedicated some time to learn some concepts of modern C++. And since I was on it why not summarizing the recent development of modern C++? The real reason is that I felt I was always using the same features of modern C++ but I felt that there were a lot of topics that I did not master or that I was not even aware of, especially in C++20.What sets C++20 apart for me is how it reshapes template programming and functional-style operations in ways that feel both futuristic and incredibly practical.

Here is my free pdf guidebook on modern C++! Download the PDF here

In the following section I will dive a bit deeper on the cool features of C++20.

Concepts: A Giant Leap for Template Clarity

Take Concepts, for example. No more cryptic template instantiation errors when you accidentally pass the wrong type. Now, you can explicitly constrain templates like this:

template <std::integral T>
T add(T a, T b) {
    return a + b;
}

This not only improves readability but makes your code self-documenting. The compiler’s error messages also become vastly more understandable. Finally some useful changes for template programming!

Ranges: Functional Elegance Meets Performance

Another feature I found compelling was the Ranges library. With range-based views and composable pipelines, you can write expressive and clean code like:

auto evenSquares = numbers 
    | std::views::filter([](int x) { return x % 2 == 0; })
    | std::views::transform([](int x) { return x * x; });

It’s lazy, elegant, and highly performant—bringing C++ closer to the clarity you often see in functional languages, but without sacrificing control. This is a nice feature that I am looking forward to start experimenting with.

Coroutines: Asynchronous Without the Headache

And then there are Coroutines. They open the door to writing non-blocking, asynchronous code in a synchronous style. Imagine building a generator that produces an infinite arithmetic sequence—without threads, without state machines—just with co_yield. I still do not fully understand how to use them.

Generator<int> countBy(int start, int step) {
    int value = start;
    while (true) {
        co_yield value;
        value += step;
    }
}

This is all powered by sophisticated compiler magic under the hood.

Conclusion

I found writing this guidebook very interesting and useful for myself to review some features of C++ that I tend to not use. I feel it’s important to refresh such concepts from time to time. I hope the guide will also be useful. I used AI to compile some examples and I have to admit that I am quite satisfied on how it turned out. It was also a while I didn’t write such a technical material.