C

1. C is commonly used to describe the C: drive or the first hard disk drive on IBM compatible computers.
   
   See document CH000799 about why the hard disk drive is assigned as C.
    
2. The abbreviation for Celsius.
3. A high-level programming language developed by Dennis Ritchie and Brian Kernighan at Bell Labs in 1972 from an almost unknown language named B. The first major program written in C was the Unix operating system, and for many years, C was considered to be inextricably linked with Unix. Below is an example of a C program that prints "Hello World!".

Also see: C++, Celsius, High-level language, Procedural language, Programming definitions