Why write in C?

Having been asked the question ‘Why would you write in C?’, I write here a few words on that. A Google search would recommend articles by people with much more expertise than me, who can go into much greater detail. The book 21st Century C may be useful as well.

Here are some of the reasons that I like C:

  • C is free, in the sense of free speech as well as free beer. The C standard is open, free implementations of C compilers (such as GCC) exist widely, and many of the libraries available are free and open source. You can distribute C code to other people, and know that they will be able to compile and run it, provided that they have a suitable platform. (In contrast, your colleague will only be able to run your Matlab programs if they too have a license for Matlab.)
  • C is a small language. The basic grammar of C consists of only a few keywords, and the standard library provides only a handful of mostly self-explanatory functions.
  • C is portable. A corollary of C’s smallness is that that a C compiler can be implemented relatively simply on many different systems. This is why C is often used for firmware, especially on small or specialised devices such as games consoles.
  • C is well-designed. For example, C has straightforward scoping rules, whereas Matlab (and other scripting languages such as PHP) tend to put almost all variables into a global scope, which increases the likelihood of ‘cross-contamination’ between scripts or different parts of a script. Matlab also has rules on naming conventions or on syntax which are unnecessarily strict; C is not so strict with these petty rules, and allows you to use the right style for each job (although it is up to you as the programmer to decide what that style is).
  • C evolves slowly. Since 1989, changes to standard C have occurred approximately once every ten years; these changes have been very incremental and almost always backwards-compatible. (That said, new libraries are written all the time, and programming styles have changed.) Contrast this with Matlab, where new versions are released twice a year and code written in older versions often fail with newer versions.
  • C is the parent of many other languages. The syntax of C has been inherited by languages such as Java, Python and PHP, and in turn by their descendants. For example, although functions for printing formatted text existed in languages before C, it is C’s printf function whose name and syntax is used by most languages.
  • C is widely used. Because of its age and its portability, C remains a standard language amongst systems programmers. Because C is relatively low-level, allowing (and often mandating) direct control over memory usage, it is used for firmware as well as things such as the Linux kernel. That said, C’s usefulness is not restricted to systems programming; the wide range of libraries available means that it is also used for applications or scientific computing.

On the other hand, C has some downsides. C is hard to learn compared to Matlab, and its low-level nature means that you have to be careful about things like memory management (which is done automatically by languages such as Java).

Creating user interfaces, graphics or plots with C is not immediately easy. All the libraries are there, but you will still have to do quite a lot of work. I usually prefer to have my C applications output data into text files, which I then give to gnuplot or Matlab if I want a plot out of them.

I wish I could give a comparison against Fortran or Python as well as Matlab, as those are other languages that are often used for scientific computing. But I don’t know either of them.

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