Summary

In this chapter, we revisited some of the important features of the C programming language. We tried to go further and show the design aspects of these features and the concepts behind them. Of course, the proper use of a feature requires a deeper insight into the different aspects of that feature. As part of this chapter, we discussed the following:

• We talked about the C preprocessing phase and how various directives can influence the preprocessor to act differently or generate a specific C code for us.
• Macros and the macro expansion mechanism allow us to generate C code before passing the translation unit to the compilation phase.
• Conditional directives allow us to alter the preprocessed code based on certain conditions and allow us to have different code for different situations.
• We also looked at variable pointers, and how they are employed in C.
• We introduced generic pointers and how we can have a function that accepts any kind of pointer.
• We discussed some issues such as segmentation faults and dangling pointers to show a few disastrous situations that can arise from misusing pointers.
• Functions were discussed next, and we reviewed their syntax.
• We explored functions' design aspects and how they contribute to a nicely shaped procedural C program.
• We also explained the function call mechanism and how arguments are passed to a function using stack frames.
• Function pointers were explored in this chapter. The powerful syntax of function pointers allows us to store logics in variable-like entities and use them later. They are, in fact, the fundamental mechanism that every single program uses today to be loaded and operate.
• Structures together with function pointers gave rise to encapsulation in C. We speak more about this in the third part of the book, Object Orientation.
• We tried to explain the design aspects of structures and their effect on the way we design programs in C.
• We also discussed the memory layout of structure variables and how they are placed inside memory to maximize CPU utilization.
• Nested structures were also discussed. We also took a look inside the complex structure variables and discussed how their memory layout should look.
• As the final section in this chapter, we talked about structure pointers.

The next chapter will be our first step in building a C project. The C compilation pipeline and linking mechanism will be discussed as part of the next chapter. Reading it thoroughly will be essential to continue with the book and proceed to further chapters.