Define header file in c programming

As the preprocessor parses the source file, each occurrence of the name is replaced by its associated text. The scope of define is limited to the file in which it is defined.

So, defines which are created in one source file are NOT available in a different source file. Join YouTube Channel. Where ;. The minimum value between 50 and 20 is: Reinforcement Learning. R Programming. React Native. Python Design Patterns. Python Pillow. Python Turtle. Verbal Ability. Interview Questions. Company Questions. Artificial Intelligence. Cloud Computing. Data Science. Angular 7.

Machine Learning. Data Structures. Below is the illustration of header file: CPP. Skip to content. Change Language. Related Articles. Table of Contents. Improve Article. Save Article. Like Article. Connect and share knowledge within a single location that is structured and easy to search.

I am just starting to learn C so hopefully this isn't a dumb question. The problem I am having is regarding header files and using define for constants. I have read that I should use the following to prevent my header from being compiled more than once. Or do I have this all completely wrong? There is no essential difference between the two defines. They define a plaintext replacement of tokens in the first case, the replacement is nothing.

There is no "magic". The compilation step that performs these substitutions is usually known as "preprocessing". And it would work just as well. The second time the compiler comes around this, because the header was included in project more than once, is that the marco is defined now and the header file doesn't get processed again. What you are reffering to is probably, that your IDE auto-generated the marco then you created the header file and that the IDE called the marco after the file for the user's convenience.

Like a another one here allready said, that you can rename the marco rename it in the whole project I mean by that and the code would compile and generally behave exactly like before.