History and Evolution of C

The C programming language was designed by Dennis Ritchie at Bell Laboratories between 1969 and 1973, primarily to rewrite and support the Unix operating system. It evolved from earlier languages named B (created by Ken Thompson) and BCPL (created by Martin Richards), inheriting their concise syntax while adding data types and richer control structures.

Understanding C's history explains many of its design decisions — its closeness to hardware, minimal runtime, and portability — all of which trace back to its original purpose: writing an efficient, portable operating system.

Timeline of key milestones: (1) 1969-1970 — Ken Thompson develops the B language at Bell Labs, itself derived from BCPL, used to write early Unix utilities. (2) 1972 — Dennis Ritchie develops C by adding a type system (int, char, etc.) and structures to B, addressing B's lack of data types. (3) 1973 — Unix's kernel is rewritten in C, proving the language's suitability for systems programming and making Unix far more portable across hardware.

(4) 1978 — Brian Kernighan and Dennis Ritchie publish 'The C Programming Language,' whose first edition described what is informally called 'K&R C,' the de facto standard for years. (5) 1989/1990 — The American National Standards Institute standardizes the language as ANSI C (also called C89), later adopted internationally as ISO C90, adding function prototypes and the void type among other improvements. (6) 1999 — The C99 standard introduces features like inline functions, the // single-line comment, variable-length arrays, and the bool type via stdbool.h. (7) 2011 — C11 adds multithreading support, improved Unicode handling, and anonymous structures/unions. Later revisions include C17 (a bug-fix update) and C23.