"C is a general purpose programming language."
The C Programming Language, Second Edition, Dennis M. Ritchie.
From the above definition of C programming language, it is clear that this programming language could be used to write any kind of software, be it a device driver, operating system, compiler, scientific software, medical software, embedded software or any software program for that matter. And yes, we have many examples of what C could do. Unix, Linux and even Windows had been written in C. Many video / computer games were written in C. Objective C, C++ were developed in C. C is most popular programming language among programmers and reson for it's popularity is it's simplicity. It's easy to learn and write code.
Some other definitions -
"C is a system programming language."
"C is a general purpose, procedural, imperative programming language."
"C is a low level programming language."
"C is a structured programming language."
All the above definitions are correct. C is a general purpose programming language as it is suited for any kind of programming requirement. It is platform independent as per ANSI standard so same source code could be compiled for any platform just we need compatible compiler which is mostly available. C is low level as we can write code in assembly notation to control the hardware directly . C is structured programming as it
In Unix or Linux system GCC [GNU Compiler Collection] is pre-installed. In MS-Windows you might have to download some compiler such as Turbo C, Visual Studio or MinGW [Minimalist GNU C/C++ compiler for windows]
Lets write our first c code as ritual followed by programmers, first code is a Hello World program, which will print "Hello World" as output on console.
} Output: Hello World
In 1972, Dennis Ritchie and Ken Thompson started writing a new programming language compiler which was needed for their project named Unix Operating System. As Ken Thompson had already written a simplified version BCPL programming language and named it as B, so they took this B to another level and named it C. At that time Ritchie and Thompson were colleagues at AT&T Bell laboratory. Later in 1978, Ritchie and Kernighan published first edition of the book The C Programming Language .
Since the first appearance of C in Version 2 Unix, it became a huge hit and popularity grew rapidly. In 1972 large part of Unix was re-written in C and in 1973 some new features were added to C and Unix was again re-written in C. With growing popularity of C it had to port to different platforms and in 1983 ANSI [American National Standard Institute] formed a committee to establish a standard specification of C. In 1989 ANSI came up with standard specification and it was called as ANSI C or c89.
C90, C99, C11 are other standard definitions revised by ISO [Internation Organisation for Standardization] respectively in the years 1990, 1999 and 2011.