Online tools for C++ developers

C++ is the main language I use. It’s what pays my bills but more than that, is what gives me a lot of joy due to its complexity and powerfulness. But many times when I’m working I miss the ability to do quick tests without having to compile the code or writing auxiliary structures.

Lucky for me (and for all the C++ developers out there) there are online tools that will ease these tasks. In this post, I’ll present some of those tools that I use more frequently and the scenarios where they are the best fit for me.

Learn Cpp

Before everything, this first tip is meant for those that are still learning or want to learn C++. Learn Cpp is a free website devoted to teaching you how to program in C++. Whether you’ve had any prior programming experience or not, the tutorials on this site will walk you through all the steps to write, compile, and debug your C++ programs, all with plenty of examples.

When someones come to me questioning what they could do to become C++ developers, Learn Cpp is my first suggestion. It approaches from the very basic syntax and constructions, passing through data types and inheritance, up to more complex topics and even updates on newer versions of C++.


C++ shell

C++ shell as the name suggests is an online C++ compiler shell. It’s much simpler than the items that are to come in this list, but it gets the job done. If you want to quickly check something and see the output, it will be enough for you. It does support C++ 98, 11, and 14 and some warnings and optimization levels, but that’s it.

This is usually my go-to whenever I want to test some small code to see if it’s behaving as I wanted and I’m not interested in anything fancier.


Online GDB

Online GDB is like the improved version of the C++ shell. It’s also an online compiler, but it also has a built-in feature for debugging using GDB. You can compile, run and debug code, not only it supports C++ (including C++ 11 to 17), it also works with languages such as Python, Rust, and many others.


Quick C++ Benchmark

Quick Bench is an online benchmarking tool intended to quickly and simply compare the performance of two or more code snippets. It does support different compilers (with many versions available), C++ from 11 to 20 (really!), different optimization levels, and other customizations.

Not only it’s super easy to set up the benchmark, but it will also create a chart with the comparison of the snippets. And if you are into it, you can still check the assembly, and see what are the instructions that are making your code slower.

Quick bench chart


Perf Bench

If Quick Bench didn’t sound right to you, maybe Perf Bench will make it. Similar to the previous item, Perf Bench it’s an online C++ code profiler. It lets you write and benchmark C++ online and see latencies on charts, comparing performance between different versions of the code.

What I really like about this tool is that it allows to nest different scopes of profilers and specify the number of loops for each profiler. Honestly, most of the time this is a bit overkill to my use, but on specific occasions, it’s exactly what I need.


Compiler Explorer (Godbolt)

Compiler Explorer is an interactive compiler explorer website. With a huge list of compilers and languages supported, you can see what’s the assembly of the code you are writing in real-time. Different tools and visualizations are available and the UI is very customizable.

Although the focus of Compiler Explorer was (and I think it still is) to convert code into the assembly, it also has the support for execution. In this talk on CppCon 2019 from Matt Godbolt, creator of the Compiler Explorer, he presents the history of Compiler Explorer, some of the newer features (at that time), and some of the behind the scenes.


Cpp Insights

Cpp Insights is a clang-based tool that does a source-to-source transformation. Its goal is to make things visible which normally, and intentionally, happen behind the scenes. As they say: It’s about the magic the compiler does for us to make things work.

You’ll be able to see what the compiler actually sees, removing a lot of the syntax sugar we are used to. You can check out the talk from Andreas Fertig on NDC Oslo 2017 where he talks about these hidden costs of the language’s features, and Cpp Insights is all about that!


Final thoughts

All the tools I talk about here are available online and have some way of sharing the code snippets with others and some are even integrated, which allows you to bring a code from one to the other with the click of a button.

This by no means will replace having a compiler installed with other libraries you are using, but still, they are great tools for quick tasks, where you want to validate a solution, compare versions of the same code, or just are interested in learning more in-depth information on the compilation/language details.

As an open-source advocate, I also want to highlight that many of these tools are open source. You can check the repositories from their sites and collaboration is welcomed.

Hope this is useful, and please share what are the online (or maybe local) tools you use that help you in the development process.

As always, I’m on Twitter @thamyk, just waiting to hear what you think!

This post is licensed under CC BY 4.0 by the author.