Update intro.md

Author: kspalaiologos

book/languages/c/intro.md

@@ -1 +1,15 @@
 # Introduction
+
+**C** is a general-purpose, imperative programming language, supporting structured programming, lexical variable scope and 
+recursion, with static, weakly enforced type system. C provides constructs that map to machine code, so it has found use in
+applications that had been coded in assembly language before, including operating systems, as well as various software for
+computers.
+
+C is an imperative procedural language. It was designed to be compiled using simple compiler, to provide low level stuff sufficent
+to replace a few tasks of assembly, and provide higher level language constructs that map efficiently to machine instructions,
+that require minimal run-time support, to increase usability of language.
+
+Despite its low-level capabilities, the language has wide cross-platform programming capabilities. A C89 program 
+that is written with portability in mind can be compiled for a very wide variety of platforms and operating systems with 
+few or no changes to its source code. The language has become available on a very wide range of platforms, from embedded
+systems to supercomputers.