When you’re learning a programming language, you need to do practice problems. Even if you don’t have much free time, short, regular practice sessions are better than long, infrequent sessions. If you have a break at work or school, that can be a great time to do some quick practice.
But what if you can’t install a development environment on your work or school computer? You might not have permission to install programs, or it might take too long and be impractical to do so. You want to focus on writing code, and not worrying about setting up your development environment. If you are using a Unix-based system, you already have access to C++ and C, but even still, you would have to do some work to run Java, Python or other languages.
If this is your situation, consider trying Ideone.com, a free online compiler and debugging tool. It supports over 60 programming languages, including Java, C++ and Ruby, so you can run short bits of code online without having to set up or install any software. If you need help figuring out how to run code, the site also has code samples you can consult.
In addition to practice, another possible application I see is that you can try out a new language without having to install a lot of software on your computer. For example, suppose you’re wondering about what language you should learn. You can do some tutorials from a few different options to see which one you like best. Then once you choose, you can set up the necessary development environment and tools on your computer. Setting up can be a confusing and discouraging process for new developers, so this tool is a good way to make try something new before you commit to that process.
There are some limitations, however. Any code you write will not have internet access, so Ideone is not the best place to practice networking code. Also, your program can read files, but not write them, so file IO code will be restricted. I have not read through all the FAQs or used it extensively yet myself, so it might have other limitations I left out. If so, please let me know and I can amend this post.