Chapter 10 – Creating Custom Data Types 
with typedef

1. The typedef keyword allows us to create synonym types that add context to variables of that type.
2. For enumeration and structure types, typedef provides a shorthand synonym. Instead of using enum List, we can use typedef to shorten it to just List. Instead of using struct Gizmo, we can use typedef to shorten it to just Gizmo. Then, we can declare variables of List and Gizmo synonym types.
3. Essentially, there is no difference. The syntax for both is identical.
4. The –Wall and –Werror switches instruct the compiler to treat any warning as an error and to cause all errors, no matter how trivial, to stop compilation.
5. Anything that does not allocate memory (typedef, enum, struct, and function prototypes) goes into a header file. Anything that allocates memory or defines functions goes into the source file, not the header.