Correct Way to Include iostream in C : iostream vs iostream.h

In modern C programming, the correct and recommended way to include the standard input/output stream library is to use include iostream. This is in stark contrast to the older iostream.h header file which was used in pre-standard C programming and is not compliant with the more recent C standards.

Understanding the Evolution of C Libraries

The standard library headers in C do not include the .h extension. This is a key difference between C and C . In pre-standard C, the iostream.h header was used, but this is now considered an outdated practice.

The use of iostream.h on modern C compilers typically results in errors or warnings due to the lack of support. Modern C compilers adhere to the C standard, which explicitly defines that certain headers should not end with the .h extension.

Modern C Practice

Since the implementation of the C standard with the C 98 specification, the correct header to use for input/output operations is:

This header is a part of the C standard library and is fully supported by modern compilers. It is designed to be consistent with the standard and ensure compatibility across different platforms and environments.

Compatibility and Compiler Variations

It's worth noting that, in some older compilers or certain specific environments, you might encounter cases where the iostream.h header is still supported. For example, in older products like Turbo C, iostream.h might work without issues.

However, for the sake of your code's portability and adherence to the latest standards, it is highly recommended to stick with iostream without the .h suffix. This will ensure that your code remains compatible with future versions of the C standard and different implementations.

Conclusion: Best Practices for C Programming

To summarize, the modern and correct way to include the iostream library in C is:

include iostream

Avoid the use of iostream.h as it is no longer a part of the standard and might cause compatibility issues. Ensuring that you follow these best practices will not only make your code cleaner but also ensure better portability and maintainability.