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1. Introduction
What is the C language? And why does it continue to attract attention today
The C language is a programming language that was created in 1972 at AT&T Bell Labs in the United States. Even today, among the many languages that exist, C still enjoys strong popularity. In particular, in embedded systems and operating system development, C is still used at the forefront.The significance of knowing history
When learning programming, it is very important to understand the background and circumstances in which a language was created and how it has evolved. Knowing the history of the C language not only deepens technical knowledge but also helps you understand its philosophy and design principles. This becomes training that cultivates a perspective that can be applied when learning other languages and frameworks.Purpose of this article
In this article, we will explain, following the course of history, the origins of the C language, its development background, standardization process, influence on other languages, and its current position. The structure is designed to be easy for beginners, so whether you are about to start learning C or have been using it without knowing its background, you are sure to discover something new.2. Origins of the C Language
BCPL, the Foundation of the C Language’s Birth
Tracing the roots of the C language leads to the BCPL (Basic Combined Programming Language), which was developed in the 1960s. BCPL was designed in 1966 by Martin Richards of Cambridge University as a simple and flexible language intended for writing compilers. This BCPL was designed without an explicit notion of “type,” treating all data as a single “word.” As a result, it offered great flexibility when writing programs and enabled efficient processing within the limited computer resources of the time. However, the lack of types also made bugs and misbehaviors more likely, and it was seen as a major area for improvement in later language designs.The Birth and Characteristics of the B Language
Derived from BCPL, the B language emerged. Around 1970, Ken Thompson at AT&T Bell Labs simplified BCPL and designed it to run on the mini‑computer “DEC PDP‑7,” creating the B language. The B language also lacked “type” in its design, just like BCPL. While this preserved program flexibility, the emergence of more powerful machines at the time began to demand stricter control and data management. In particular, the evolution of hardware environments such as 16‑bit and 32‑bit systems made the clarification of “type” an unavoidable issue.Laying the Groundwork for the Birth of C
The B language was used in the development of early versions of UNIX, but its language constraints gradually became obstacles to development. In particular, the difficulty of handling complex structures, pointer manipulation, and ensuring type safety became evident, revealing the limits of B. In this context, the “C language” emerged as an improved version of B. The next chapter will explain in detail how C was created and what characteristics it possessed.
3. Birth of the C Language
Development by Dennis Ritchie
1972, at the AT&T Bell Labs in New Jersey, USA, the C language was developed by Dennis Ritchie (Dennis M. Ritchie). He designed C as an improved version of the B language created by his colleague Ken Thompson. By introducing a concept of types and giving it a structure that could use hardware resources efficiently, he crafted a more refined low-level language.Origin of the C Language Name
The name C comes from its evolution from the predecessor “B language.” It’s simply because C follows B in the alphabet. This also conveyed the message that it was an improved version on the line of B language. It is not an acronym for any particular words.Innovative Features of the C Language
The biggest feature of C is its design philosophy that sits between high-level and low-level languages. In other words, it offers a syntax that is easy for humans to understand while allowing instruction control close to machine code, making it a very balanced language. Below are some of the main features of the C language:- Introduction of a Type System: Clearly defines the data types (int, char, float, etc.) that variables handle.
- Pointers: Ability to manipulate memory addresses directly, enabling dynamic memory management and passing function addresses.
- Structures (struct): Allows grouping of multiple different types of data together.
- Function Decomposition: Dividing processing into functions enhances modularity and reusability.
- Preprocessor Directives: Mechanisms like
#defineand#includethat let you write commands executed before compilation.
Changes Brought About by the Arrival of C
With its introduction, C made it possible to write “highly portable code” that was difficult to achieve with traditional assembly or unstructured languages. The groundbreaking idea that the same program could run on various hardware as long as a compiler existed reshaped the norms of software development.4. Relationship with UNIX
Behind the Scenes of UNIX Development and the Advent of the C Language
In the early 1970s, AT&T Bell Labs was developing UNIX as the next-generation operating system. Early UNIX was written in assembly language and depended on the instruction set of each platform, making it poorly portable and difficult to modify or maintain. Amid this, under the leadership of Dennis Ritchie and Ken Thompson, a bold effort began to reimplement UNIX in the C language. The impact of this choice on the programming world was immeasurable.Reimplementation of UNIX in C (1973)
In 1973, UNIX was reconstructed in the C language. This was groundbreaking at the time, as it was unprecedented for core OS software to be written in a high-level language that did not depend on hardware. The benefits of this C-language implementation were substantial, yielding the following advantages.- High portability: UNIX written in C could run on other machines as long as a compiler was available.
- Improved maintainability and extensibility: The readable, well-structured syntax dramatically increased development efficiency.
- Expansion of the developer community: Other universities and companies began using C and UNIX, making knowledge sharing easier.
The Mutual Development Relationship Between UNIX and the C Language
UNIX and the C language have a mutually complementary evolutionary relationship. The portability and efficiency of C supported UNIX’s diverse hardware deployments, and UNIX’s success demonstrated C’s reliability and usefulness as a real-world case study. The development style established during this period—’UNIX + C’—became the standard model for subsequent software development, forming a technical lineage that extends to modern OSes such as Linux, BSD, and even macOS and Android.5. Standardization and Evolution
The Emergence of K&R C (1978)
In 1978, when the C language began to spread widely, the book ‘The C Programming Language’ co‑authored by Brian W. Kernighan and Dennis Ritchie became the de facto standard for C worldwide. This version of C is called “K&R C (Kernighan & Ritchie C)”. K&R C allowed omitted function prototypes and lax type checking, which from a modern perspective meant a highly permissive style of coding. However, this excessive flexibility began to be seen as problematic for large‑scale development and safety.
Standardization with ANSI C (C89/C90)
As C became used worldwide, differences in behavior between compilers began to trouble developers. To address this, in 1983 ANSI (American National Standards Institute) started standardizing C, and in 1989 the official standard was established as “ANSI C (C89)”. Furthermore, in 1990 it was recognized as an international standard by ISO, and is also referred to as “C90”. ANSI C introduced the following improvements:- Explicit function prototypes (enhanced type checking)
- Expanded standard library (e.g.,
<stdio.h>,<stdlib.h>etc.) - Introduction of enum types,
const,volatile - More precise definitions of types and memory operations
C99, C11, C17, and C23
Even after ANSI C, the C language has continued to be revised to meet the demands of the times.- C99 (1999) introduced more flexible variable declaration locations,
//comments, variable‑length arrays, theinlinekeyword, and other modern syntax. - C11 (2011) added multithreading support (
<threads>), atomic operations, Unicode support, security enhancements, making the language more robust and versatile. - C17 (2017) was essentially a maintenance release, focusing on bug fixes and clarifications of existing specifications.
- C23 (planned for 2023 – final draft approved) aims to improve compatibility with modern C++, adding constexpr‑like features and support for more concise syntax, further modernizing the language.
C’s Strengths as a Long‑Lived Language
These standardization trends show how C has continuously met evolving needs while preserving its core design philosophy. A language that has remained in use for decades is unparalleled, underscoring the timelessness of C’s design.6. Influence of C and Derivative Languages
The Massive Impact C Has Had on Other Languages
C is more than just a programming language; it directly influenced the design of countless languages that followed. C’s syntax, memory‑management philosophy, and control structures (likeif, for, while) have become what could be called a “common language” of programming languages. The influence is especially evident in the following languages:- C++ C++ extends C by adding object‑oriented features. While maintaining compatibility with C, it introduces advanced concepts such as classes, inheritance, and polymorphism.
- Java Heavily influenced by C++, it eliminates pointer manipulation and runs on a virtual machine (JVM) to prioritize safety and portability. Its syntax is based on the C family, so knowing C makes transitioning to Java relatively smooth.
- C# Developed by Microsoft, its syntax is rooted in the C family but is tightly integrated with the .NET framework. It is often described as a hybrid between Java and C++.
- Objective‑C, Swift（Apple ecosystem） Objective‑C blends C with Smalltalk’s messaging capabilities, while Swift, as its successor, adopts a modern syntax yet retains a strong influence from C‑style syntax.
The Strength of C in Embedded and OS Development
C’s greatest strength is its ability to provide control at a level close to the hardware. Because of this, C remains the primary language in areas such as:- Embedded systems: C is used in many microcontrollers (MCUs) found in consumer electronics, automotive devices, medical equipment, and more.
- OS development: The Linux kernel is written in C, and C also plays a crucial role inside macOS and Windows.
- General system programming: device drivers, compilers, database engines, etc.
Why Learning C Is Still Valuable Today
Many people shy away from C, labeling it an “old language,” but it is actually the best teaching tool for grasping the fundamentals of programming and low‑level mechanisms.- Learning pointers clarifies how memory is handled
- Learning how to use types and structs builds a foundation in data design
- The simple syntax hones logical thinking
7. Summary
Looking Back at the History of the C Language
C language has long been supported since its development by Dennis Ritchie in 1972 as a language that laid the foundation for software development. Its roots lie in BCPL and the B language, and, spurred by the reimplementation of UNIX, it spread explosively among researchers and engineers worldwide. Since then, it has undergone ANSI standardization (C89/C90) and subsequent updates such as C99, C11, C17, and C23, and it continues to be used as a still-active programming language more than 50 years later.What the C Language Brought
The C language has provided the following important values to the engineering community:- Portability across platforms
- Control at a level close to the hardware
- Fundamental syntax for programming languages
- Influence on derivative languages such as C++ and Java
The Value of Learning It Remains Unchanged
While high-level languages such as Python and JavaScript attract attention today, learning C still holds great significance. Studying C is highly effective for cultivating the “core programming skills” such as memory management, data structures, and low-level control. In particular, understanding C becomes a powerful asset for the following people:- Engineers aiming for embedded systems or IoT development
- People interested in system programming such as operating systems or compilers
- Students who want to seriously acquire the fundamentals of CS (computer science)
