Q&A
Q What effect do comments have on a program?
A Comments are for programmers. When the compiler converts the source code to object code, it throws the comments and the white space away. This means that they have no effect on the executable program. A program with a lot of comments executes just as fast as a program with few comments. Comments do make your source file bigger, but this is usually of little concern. To summarize, you should use comments and white space to make your source code as easy to understand and maintain as possible.
Q What is the difference between a statement and a block?
A A block is a group of statements enclosed in braces ({}). A block can be used in most places that a statement can be used.
Q How can I find out what library functions are available?
A Many compilers come with online documentation dedicated specifically to documenting the library functions. They are usually in alphabetical order. Appendix C, “Common C Functions,” lists many of the available functions. After you begin to understand more of C, it would be a good idea to read that appendix so that you don’t rewrite a library function. (There’s no use reinventing the wheel!)