From ALGOL to C: The Epic Journey That Shaped Modern Computing

Chronology of the C Family Development

In the late 1950s many new programming languages were created for specific hardware such as UNIVAC and IBM 700 series, making cross‑system communication difficult. Researchers proposed a hardware‑independent scientific language, leading to the International Algebraic Language (IAL), later renamed ALGOL, the first member of the ALGOL family.

ALGOL was the first clearly defined high‑level language and became the standard for algorithm description, inspiring later languages such as Pascal, Ada, and C.

Alan J. Perlis presented the Algol 60 report, establishing Algol 60 as a milestone that turned programming languages into an independent scientific discipline and laid the foundation for software automation and reliability.

In 2002 Edsger Dijkstra described Algol 60 as a “miracle” that marked the birth of computer science.

Subsequent languages derived from ALGOL include CPL (1963, Cambridge), BCPL (1967, simplified CPL), B (1969, Ken Thompson’s simplification of BCPL), and finally C (1972, Dennis Ritchie’s extension of B).

Thompson used B to write the first UNIX kernel, assembler, shell and file system on a DEC PDP‑7, and Ritchie later extended B to create C, adding a type system to handle the diverse data objects of the PDP‑11.

C was completed in early 1973, retained B’s low‑level efficiency while adding data types, and was quickly used to rewrite UNIX, proving the portability of the operating system by 1977.

From 1975 onward C was ported to many machines, from micro‑computers to supercomputers, and became the de‑facto language for system software, databases, office suites, antivirus, network protocols, and many other core applications.

History of the C Language

C is a general‑purpose, procedural high‑level language; the UNIX kernel, C compiler, and most UNIX applications are written in C.

The earliest prototype of C was ALGOL 60.

1963 Cambridge developed CPL.

1967 Matin Richards simplified CPL into BCPL.

1970 Ken Thompson at Bell Labs created B from BCPL and wrote the first UNIX system.

1973 Dennis Ritchie designed C based on B and BCPL.

Shortly after, the UNIX kernel and applications were rewritten in C.

Versions of the C Language

K&R C (1978) – The first edition of “The C Programming Language” by Dennis Ritchie and Brian Kernighan, which became the de‑facto standard.

C89 (ANSI C) – In 1989 the ANSI X3J11 committee adopted the C89 standard, providing an unambiguous, platform‑independent definition.

C90 (ISO C) – The same specification was adopted by ISO in 1990, identical to C89.

C95 – A minor extension of C90 published in 1995.

C99 – Introduced in 1999; GCC can be invoked with -std=c99 or -std=iso9899:1999.

C11 – The current standard (ISO/IEC 9899:2011); GCC options -std=c11 or -std=iso9899:2011.

ISO defines two levels of C library support: full library functions and a basic set (e.g., <float.h>, <limits.h>, <stdarg.h>, <stddef.h>, with additional headers such as <stdbool.h>, <stdint.h>, <stdalign.h>, <stdnoreturn.h>).

Features of the C Language

C is a mid‑level language that combines high‑level data structures with low‑level hardware access, allowing direct manipulation of bits, bytes, and addresses.

It is a structured language that separates code and data, supports functions, loops, and conditionals, and enables clear, maintainable programs.

C offers a rich set of data types, pointers for efficient memory handling, strong portability, and powerful data‑processing capabilities, making it suitable for system software, graphics, and animation.

Advantages of the C Language

It provides high‑level structure with low‑level resource control, achieving execution speed only 10‑20 % slower than assembly while being more productive than other high‑level languages.

Rich operators, data types, and expressions give excellent adaptability for program design.

Supports function‑based modular design, multi‑file projects, and independent compilation, ideal for large complex programs.

The language is concise, flexible, and easy to write.

Code and executables are highly portable across platforms.

Disadvantages of the C Language

For large, complex projects with many developers, C can become cumbersome due to lack of object‑oriented features and weaker type safety.

I/O and string handling are more complex than in many modern languages, and graphics programming is non‑trivial.

Weak encapsulation and limited safety mechanisms make data security a concern.

Loose type checking and no automatic bounds checking can lead to unsafe code, increasing the learning curve.

While pointers give powerful low‑level access, they also introduce safety risks that later languages (C++, Java) address.

Overall, C’s type‑checking is relatively weak and it lacks built‑in structures for code reuse.