Can include files be nested? in C programming

Can include files be nested?

Yes. Include files can be nested any number of times. As long as you use precautionary measures (see FAQ
V.3), you can avoid including the same file twice.
In the past, nesting header files was seen as bad programming practice, because it complicates the dependency

tracking function of the MAKE program and thus slows down compilation. Many of today’s popularcompilers make up for this difficulty by implementing a concept called precompiled headers, in which all headers and associated dependencies are stored in a precompiled state.

Many programmers like to create a custom header file that has #include statements for every header needed
for each module. This is perfectly acceptable and can help avoid potential problems relating to #include files,
such as accidentally omitting an #include file in a module.

Cross Reference:

V.3: How can you avoid including a header more than once?
V.4: Can a file other than a .h file be included with #include?

V.12: What is the difference between #include <file> and #include “file”?
V.15: How many levels deep can include files be nested?