C Language: The Programming Cornerstone and Technical Legend of Half a Century

I am Feri, a veteran with 12 years of experience in the coding world. From Java to HarmonyOS, from embedded systems to AI, I firmly believe that the foundation of all complex systems lies in the most basic languages. Today, let us unveil the mystery of the C language—this ‘ancient language’ born in the Unix laboratory, and how it has become the genetic chain of the modern programming world.

The Birth of Technical Genes: The Evolutionary Code from B to C

(1) B Language: The Minimalist Hardware Communicator (1969-1972)

In front of the DEC PDP-7 minicomputer’s screen, Ken Thompson faced an unprecedented challenge: how to implement low-level control of the operating system using a minimalist language on a machine with only 8KB of memory?

Design Philosophy: Simplified from the BCPL language, removing all unnecessary syntax, retaining onlyauto, if, while, and 14 other keywords
Fatal Flaw: No data type distinction (all variables default toint), relying on hardware byte order, and low compilation efficiency for complex expressions
Historical Contribution: Completed the development of the first Unix prototype system, proving the disruptive idea that ‘high-level languages can handle system-level programming’

C Language Mastery: Understanding the Past and Present of C Programming

(2) Dennis Ritchie’s Key Improvements (1972-1973)

While Thompson was busy porting Unix, his colleague Dennis Ritchie was conducting a silent revolution:

Foundation of Type System

Introducedchar/int/float/double basic types, supportingstruct custom data structures
First introduced pointer type*, enabling explicit manipulation of memory addresses (int *p = &var)

Evolution of Control Structures

Improvedfor loop syntax (separating initialization/condition/iteration)
Addedswitch branching structure, replacing cumbersome nestedif-else

Cross-Platform Breakthrough

Designed an intermediate code representation independent of hardware, achieving platform adaptation through the preprocessor#include

These improvements allowed the new language to manipulate memory like assembly while possessing the abstraction capabilities of high-level languages. In 1973, 90% of the Unix V4 code was rewritten in the new language, and ‘C language’ officially took the historical stage.

The Transformation of an Industrial-Grade Language: The Path to Standardization and Technical Moat

(1) The Birth of ANSI C: From Laboratory to Industry (1989)

As the C language spread beyond Bell Labs, differences in compiler implementations became a significant risk:

Core Issue: K&R C (syntax defined in ‘The C Programming Language’) lacked strict specifications,main() return values, array out-of-bounds behavior, etc., were undefined
Standardization Achievements

Clarified data type value ranges (e.g.,int at least 16 bits,long at least 32 bits)
Introduced function prototype declarations (solving parameter type checking issues)
Established standard library specifications (standardizing header files likestdio.h/stdlib.h)

(2) Continuously Evolving Language Standards (1999-Present)

The C language has always adhered to the principle of ‘evolution rather than revolution’:

Standard Version	Key Features	Technical Impact
C99	Variable Length Arrays (VLA), Boolean Type`<span>_Bool</span>`, Complex Type`<span>_Complex</span>`	Widely used in scientific computing
C11	Multithreading support (`<span>pthreads</span>` extension), memory alignment`<span>_Alignas</span>`	Optimizations for embedded systems and high-performance computing
C18	Simplified preprocessing rules, strengthened type safety checks	Support for modern static analysis tools (like Clang-Tidy)

These features allow the C language to maintain its original efficiency while gradually acquiring the ability to handle complex scenarios.

Dominant Applications: The Foundational Power from 0 to 1

(1) The Genetic Code of Operating Systems

Linux Kernel: 97% of the 28 million lines of code are written in C, relying on its pointer operations for memory management (slab allocator) and process scheduling (CFS algorithm)
Windows Kernel: Despite extensive use of C++, core modules (like NT kernel objects) are still implemented in C, ensuring extreme efficiency in hardware interaction
Embedded Systems: In STM32 microcontroller development, C directly manipulates registers (*(volatile unsigned int*)0x40010800 = 0x01), achieving nanosecond-level precision control

(2) The Underlying Engine of High-Performance Computing

Game Development: Core modules of Unreal Engine 4 (rendering pipeline, physics engine) are implemented in C, ensuring computational efficiency for processing millions of triangles per second
Database Systems: MySQL’s storage engine (InnoDB) implements B+ tree indexing through C pointer operations, achieving microsecond-level data retrieval latency
Cryptographic Algorithms: OpenSSL’s AES/DES implementations are entirely written in C, meeting the stringent performance requirements of cryptography while maintaining cross-platform compatibility

(3) The ‘Mother Tongue’ Status of Programming Languages

Almost all modern languages flow with the blood of C:

**C++**: Fully compatible with C syntax, enabling seamless interaction with C code throughextern "C"
Java: The early JVM was written in C, and its basic data types (likeint/char) are fully inherited from C language specifications
Python: The core interpreter (CPython) is implemented in C, breaking performance bottlenecks through C extension mechanisms (like Numpy)

The Technical Legacy of C Language: Three Letters of Advice for New Era Developers

(1) The Best Window to Understand the Essence of Memory

In today’s world dominated by Java/C#, why is it still necessary to master C?

// Classic dangling pointer problem demonstration
int* dangling_pointer() {
    int localVar = 10;
    return &amp;localVar; // Dangerous! Returning address of local variable
}

// Memory leak example (a must-learn for non-GC languages)
int* memory_leak() {
    int* ptr = (int*)malloc(sizeof(int));
    return ptr; // Caller did not free memory
}

These issues, which are automatically handled in managed languages, are the most precious gifts that C language leaves to developers—a deep understanding of memory lifecycle is the underlying logic support for all high-level programming.

(2) The Inevitable Path of Embedded Development

When you need to implement an RTOS on an 8-bit microcontroller:

You must use C to manipulate registers for interrupt handling
You need to manually manage limited RAM resources (to avoid stack overflow)
You must understand the impact of byte alignment on Flash usage

In these scenarios, the ‘hardware proximity’ feature of C becomes the only choice.

(3) System-Level Programming Mindset Training

C language teaches us:

Performance Awareness at Zero Abstraction Level: Every function call and pointer dereference has clear time/space overhead
Extreme Consideration of Boundary Conditions: Array out-of-bounds, integer overflow, etc., must be resolved at the coding stage
Wisdom of Cross-Platform Implementation: Writing code compatible with different compilers through#ifdef preprocessor directives

The Future is Here: The New Era Mission of C Language

In the rise of IoT and edge computing, the C language is ushering in new opportunities:

HarmonyOS Kernel: Some core modules are developed in C, ensuring the efficiency and real-time nature of device drivers
RISC-V Ecosystem: As the primary programming language for the open-source instruction set, C language promotes the popularization of chip-level software development
Safety-Critical Systems: In fields like avionics and medical devices, the deterministic execution characteristics of C language are irreplaceable

Finally, a word for all developers: If you want to truly understand how computer systems work, C language is the mountain you must climb. It won’t help you quickly write web pages or apps, but it will open the door to operating systems, compilers, and hardware interaction—these are the core competitive advantages of software technology.

Follow me, in the next article we will delve into the core mechanisms of C language, analyzing key technologies such as pointers, memory management, and preprocessing, taking you from ‘knowing how to code’ to ‘understanding the essence.’

// Life philosophy written in C language:
int main() {
    while (life_is_meaningful()) {
        learn_c_language();  // Continuous learning is the correct direction of the pointer
        solve_real_problems();
    }
    return 0;  // Just hope that at the end, there are no memory leaks, and no regrets in life
}