The basics of C

C is a programming language of many different dialects, similar to the way that each spoken language has many different dialects. In C, dialects don't exist because the speakers live in the North or South. Instead, they're there because there are many different compilers that support slightly different features. There are several common compilers: in particular, Borland C++, Microsoft C++, and GNU C. There are also many front-end environments for the different compilers--the most common is Dev-C++ around GNU's G++ compiler. Some, such as GCC, are free, while others are not. Please see the compiler listing for more information on how to get a compiler and set it up. You should note that if you are programming in C on a C++ compiler, then you will want to make sure that your compiler attempts to compile C instead of C++ to avoid small compatibility issues in later tutorials.

Each of these compilers is slightly different. Each one should support the ANSI standard C functions, but each compiler will also have nonstandard functions (these functions are similar to slang spoken in different parts of a country). Sometimes the use of nonstandard functions will cause problems when you attempt to compile source code (the actual C code written by a programmer and saved as a text file) with a different compiler. These tutorials use ANSI standard C and should not suffer from this problem; fortunately, since C has been around for quite a while, there shouldn't be too many compatibility issues except when your compiler tries to create C++ code.

If you don't yet have a compiler, I strongly recommend finding one now. A simple compiler is sufficient for our use, but make sure that you do get one in order to get the most from these tutorials. The page linked above, compilers, lists compilers by operating system.

Every full C program begins inside a function called "main". A function is simply a collection of commands that do "something". The main function is always called when the program first executes. From main, we can call other functions, whether they be written by us or by others or use built-in language features. To access the standard functions that comes with your compiler, you need to include a header with the #include directive. What this does is effectively take everything in the header and paste it into your program.