Why the C Extension is .cpp and Not .c

The C programming language, as we know it today, uses the .cpp file extension rather than the more straightforward .c extension. This choice was made for a variety of historical, technical, and community reasons, all contributing to a standardized and consistent development environment for users of the language.

Historical Context

The historical context of the C language is crucial to understanding why it uses .cpp instead of .c. C was derived from the C programming language, but the creators had a clear reason to differentiate C files from their C counterparts. The choice of .cpp was made to emphasize this relationship while also signaling to users that the file contains C code, which has additional features and syntax over C.

File System Compatibility

Another factor in the decision to use .cpp is related to file system compatibility and conventions. Some file systems and operating systems have limitations or conventions that can be problematic with certain file extensions. For instance, the presence of a plus sign ( ) in .c could pose issues with some systems that may not handle extensions with special characters.

This concern led to the selection of .cpp over .c, ensuring better compatibility and recognition across different operating systems and file systems.

Simplicity and Convention

The simplicity and alignment with existing naming conventions also played a role in the adoption of .cpp. In the programming community, .cpp is simpler and more intuitive compared to other potential names for C files. It avoids the complexity of using special characters in file names, reducing the likelihood of confusion or errors among developers.

Standardization

The use of .cpp has become a widely accepted standard within the programming community. Standardizing file extensions promotes consistency in file naming across different projects and environments, making it easier for developers to identify and manage code files. This standardization helps streamline workflows and improve collaboration among developers working on the same or different projects.

Early Development and Naming Conventions

The choice of .cpp extends beyond just the C language. It is also influenced by the early development of the language itself. For instance, the original C compiler, known as the C Pre Processor (cpp), had its own file extension. To avoid confusion with the .cpp files, the extension .cc was briefly used before settling on .cpp.

The .cc extension was a natural choice for Microsoft, where command-line usage was less common. However, the rise of Unix-based systems and the GNU GCC compiler, which initially used .cc, led to the widespread adoption of .cpp. This extension is seen as a more logical and intuitive choice, as it explicitly indicates C code while avoiding the possibility of being mistaken for the C Pre Processor files.

It is worth noting that at Microsoft, the use of both .cpp and .cxx (where .cxx represents .cpp with an additional character) is quite common. This coexistence of multiple extensions, however, reflects the randomness and debate that often accompanies such decisions within a development environment where multiple compilers and standards may be in use.

Despite the variety of extensions used, the .cpp extension has become the de facto standard in the C programming community, ensuring consistency and reducing potential confusion for developers. As the language continues to evolve, the choice of file extensions remains an important aspect of its development and usage.