Why C Still Rules: Performance, Safety, and the Future of Programming Languages

Evaluating any programming language inevitably draws criticism, a phenomenon the author humorously calls the “二逼” effect.

As the author of several C language books and the translator of "C Language New Thinking, Second Edition," I feel responsible for systematically presenting C’s characteristics and future, especially for newcomers worried that C might become obsolete like Fortran or Perl.

According to the well‑known TIOBE language popularity index, both Java and C are declining, with lower‑ranked languages gaining share.

Programming languages ultimately aim to improve either hardware execution efficiency or developer productivity, but these goals cannot coexist; you must choose one.

C excels at hardware efficiency—no competitor can match its low‑level access. For example, an array int a[3] compiles to a base‑address plus offset, the fastest possible memory access for a computer.

However, this extreme efficiency sacrifices usability and safety: C cannot store mixed types in an array, offers no bounds checking, and tolerates dangerous out‑of‑bounds errors.

C’s philosophy of “trust the programmer” focuses solely on speed, caring little about programmer fatigue or safety.

Non‑C languages prioritize developer efficiency, providing dynamic or safe data structures, but any added safety layer prevents them from beating C’s raw speed.

Some question whether faster software is necessary given cheap hardware, yet modern applications—games, 3D rendering, autonomous driving—demand real‑time performance and low energy consumption.

Computation speed alone is insufficient; complexity, real‑time constraints, and power limits dominate, as illustrated by NASA’s 32‑bit CPUs on spacecraft.

New languages like D aim to match C’s speed without its pitfalls, but adoption is limited because massive existing codebases (Linux, Windows, macOS, VxWorks) are written in C.

NASA’s stringent testing illustrates why many legacy C modules cannot be altered without extensive verification.

C’s decline is partly due to tasks better suited to higher‑level languages; Windows introduced MFC to wrap C APIs, later replaced by C# for GUI development. Java similarly emphasizes networking, safety, and cross‑platform support, avoiding low‑level performance competition.

With the rise of embedded, real‑time, AI, robotics, and autonomous systems, C remains the core language for these domains and is expected to stabilize and possibly regain prominence.

While Java faces competition from Python for flexibility and from platform‑specific languages (Swift, Kotlin, Go), it will likely persist in large, non‑real‑time, cross‑platform applications.

C++ will not replace C; objects introduce overhead and inheritance brings complexity, a sentiment echoed by Java’s creator who would remove objects if redesigning the language.

In conclusion, no one can predict the future, but C’s unique performance characteristics ensure its continued relevance in critical system software.