I have written C++ for nearly 30 years. I had been advocating that it was the best language 🤣, until my love moved to Python a few years ago. I will still say C++ is a very powerful and unique language. It is probably the only language that intersects many different software layers. It lets programmers control the bit-level details, and it has the necessary mechanisms to allow programmers to make appropriate abstractions—arguably one of the best as it provides powerful generics, which are becoming better and better with the upcoming concepts and ranges in C++20. It has very decent optimizing compilers, and suitably written C++ code performs better than nearly all other languages. Therefore, C++ has been widely used in not only low-level stuff like drivers, but also libraries and applications, especially where performance is wanted, like scientific computing and games. It is still widely used in desktop applications, say, Microsoft Office and Adobe Photoshop. The power does come with a price: it is probably the most complicated computer language today. Mastering the language takes a long time (and with 30 years’ experience I dare not say I have mastered the language). Generic code also tends to take a long time to compile. Error messages can be overwhelming, especially to novices. I can go on and on, but it is better to stop here, with a note that the complexity and cost are sometimes worthwhile, in exchange for reduced latency and reduced power usage (from CPU and memory).
Python is, on the other hand, easy to learn. It is not a toy language, though: it is handy not only to novices, but also to software veterans like me. The change-and-run cycle is much shorter than C++. Code in Python is very readable, partly because lists, sets, and dictionaries are supported literal types (you cannot write in C++ an expression like {"one": 1} and let compiler deduce it is a dictionary). It has features that C++ has lacked for many years: generator/coroutine, lazy range, and so on. Generics do not need special support, as it is dynamically typed (but it also does not surprise programmers by allowing error-prone expressions like "1" + 2, as in some script languages). With a good IDE, the argument on its lack of compile-time check can be crushed—programmers can enjoy edit-time checks. It has a big ecosystem with a huge number of third-party libraries, and they are easier to take and use than in C++ (thanks to pip). The only main remaining shortcoming to me is performance, but: 1) one may write C/C++ extensions where necessary; and 2) the lack of performance may not matter at all, if your application is not CPU-bound. See my personal experience of 25x performance boost in two hours.
I used Java a long time ago. I do not like it (mostly for its verbosity), and its desktop/server implementation makes it unsuitable for short-time applications due to its sluggish launch time. However, it has always been a workhorse on the server side, and it has a successful ecosystem, if not much harmed by Oracle’s lawyers. Android also brought life to the old language and the development communities (ignoring for now the bad effects Oracle has brought about).
C# started as Microsoft’s answer to Java, but they have differed more and more since then. I actually like C#, and my experience has shown it is very suitable for Windows application development (I do not have experience with Mono, and I don’t do server development on Windows). Many of its features, like LINQ and on-stack structs, are very likeable.
C is a simple and elegant language, and it can be regarded as the ancestor of three languages above (except Python), at least in syntax. It is the most widely supported. It is the closest to metal, and is still very popular in embedded systems, OS development, and cases where maximum portability is wanted (thus the wide offerings from the open-source communities). It is the most dangerous language, as you can easily have buffer overflows. Incidentally, two of the three current answers to ‘How do you store a list of names input by the user into an array in C (not C++ or C#)?’ can have buffer overflows (and I wrote the other answer). Programmers need to tend to many details themselves.
I myself will code everything in Python where possible, as it usually requires the fewest lines of code and takes the least amount of time. If performance is wanted, I’ll go to C++. For Windows GUI applications, I’ll prefer C#. I will write in C if maximum portability and memory efficiency are wanted. I do not feel I will write in Java, except modifying existing code or when the environment supports Java only.
[I first posted it as a Quora answer, but it is probably worth a page of its own.]
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