History of C Language
Origin of C Language
The story of C begins not with C itself, but with the languages that came before it. Understanding this evolutionary chain — BCPL → B → C — helps you appreciate why C was designed the way it was and why it became so influential.
C was born out of a practical need: to write an operating system that was powerful, portable, and fast. Before C, operating systems were written in assembly language — which was fast but completely hardware-specific. If you moved to a different computer, you had to rewrite everything from scratch.
Before C, if you wrote an OS in assembly for Computer A, it would NOT run on Computer B. C gave programmers the power of low-level control WITH the portability of a higher-level language. This was revolutionary.
BCPL and B Language
BCPL (1967)
BCPL (Basic Combined Programming Language) was created by Martin Richards at the University of Cambridge in 1967. It was designed to write compilers and operating systems. Key features:
- Typeless language — everything was a "word" (machine word)
- Very simple — easy to implement on many machines
- Had direct memory access using operators
BCPL was used to write the first version of the BCPL compiler itself — an early example of bootstrapping a language.
B Language (1969)
Ken Thompson at Bell Labs created the B language in 1969, based on BCPL. He stripped down BCPL to create a simpler language suited for the early Unix systems being developed at Bell Labs. B was used to write early versions of Unix, but it had serious limitations:
- Still typeless — no distinction between integers, characters, pointers
- Slow — because it used a word-addressable memory model
- Couldn't efficiently support floating-point numbers
These limitations pushed Dennis Ritchie to create a new, improved language.
Dennis Ritchie & Bell Labs – Birth of C (1972)
Dennis MacAlistair Ritchie (1941–2011) was an American computer scientist who worked at Bell Labs. Between 1969 and 1973, he developed the C programming language primarily to rewrite the Unix operating system.
| Language | Creator | Year | Institution |
|---|---|---|---|
| BCPL | Martin Richards | 1967 | Univ. of Cambridge |
| B | Ken Thompson | 1969 | Bell Labs, AT&T |
| C | Dennis Ritchie | 1972 | Bell Labs, AT&T |
What Made C Different from B?
- Data Types — C introduced
int,char,float,double— making code safer and more efficient - Structs — the ability to group data together
- Pointers with types — typed pointer arithmetic, far more powerful than B's approach
- Preprocessor —
#include,#definemacros
Dennis Ritchie co-created both C and Unix. In 2011, he received the Japan Prize for Information and Communications. Bill Gates once said: "The tools that Dennis built — and their direct descendants — run practically everything today." He passed away on October 12, 2011.
C and UNIX – The Perfect Partnership
In 1973, Ken Thompson and Dennis Ritchie rewrote the Unix operating system kernel in C. This was a landmark moment in computing history for two reasons:
- Unix became one of the first operating systems written in a high-level language (instead of assembly)
- This proved that C was powerful enough for systems programming
Because Unix was written in C, porting Unix to a new machine just required writing a C compiler for that machine — then Unix could run on it. This portability caused Unix (and C) to spread rapidly through universities and research institutions in the 1970s.
The famous book "The C Programming Language" by Brian Kernighan and Dennis Ritchie (published 1978, also known as "K&R C") became the definitive reference for the language and is still considered one of the greatest programming books ever written.
C Language Standards Timeline
As C spread and compilers appeared from different companies, there were inconsistencies between implementations. This led to standardization efforts:
| Standard | Year | Key Additions |
|---|---|---|
| K&R C | 1978 | Original C as described in "The C Programming Language" book |
| C89 / ANSI C | 1989 | First formal standard by ANSI. Function prototypes, void, const, enum |
| C90 | 1990 | Same as C89, adopted by ISO (minor differences) |
| C99 | 1999 | Inline functions, long long int, variable-length arrays, // comments, bool, complex |
| C11 | 2011 | Multi-threading support (_Thread_local), anonymous structs/unions, improved Unicode |
| C17 | 2018 | Bug fixes for C11, no major new features. Current most widely used standard. |
| C23 | 2023 | New attributes, bool/true/false as keywords, improved type safety |
For learning: use C99 or C11. Most modern compilers (GCC, Clang) support C11 by default. For exams (GATE, B.Tech): focus on ANSI C / C89. To compile with a specific standard: gcc -std=c11 program.c
Summary
- C evolved from BCPL (1967) → B (1969) → C (1972)
- Created by Dennis Ritchie at Bell Labs, AT&T
- Originally developed to write the UNIX operating system
- The 1978 K&R book established C as the universal systems language
- Current standard is C17; latest is C23
- C remains relevant 50+ years later in OS, embedded, and database development