Comments: At the top of a program, there should be a few lines enclosed 
between the symbols /* and */ that supply information about the program's 
purpose and its author. These lines are comments. Their purpose is to 
inform the human reader, not the computer, and so they are ignored by 
the compiler. Comments also can and should appear throughout the program, 
wherever they could help a reader understand the form or function of the 
code.

/*  Traditional C development environments are command-line oriented:   
 * they force us to use separate commands to edit, compile, link, and run  
 * our programs. Often, however, there's a single command that combines 
 * compiling and linking. The workstations we use, for example, provide 
 * the popular (and free!) GNU C compiler (gcc), which lets us use
 *
 *        gcc -ansi program1.c -o program1
 *
 * to form an executable program from the source  code.
 *
 * This command looks complex. In reality, however, it's quite 
 * straightforward. The -ansi tells the GNU compiler to compile program1.c 
 * with ANSI-standard C (as opposed to pre-ANSI C, and without any 
 * GNU-specific extensions). The -o program1 tells it to put the resulting 
 * executable program in a file named program1 (as opposed to following the 
 * UNIX tradition and creating an executable named a.out).
 *
 * These command-line compilers are easy to learn how to use, provide 
 * fast compilation, and let us use our favorite editor to enter our 
 * programs. But they have several major drawbacks: incremental program 
 * development is time-consuming, and correcting errors is a potentially 
 * painful process. Before we can compile our program, we usually have to 
 * save our file and leave the editor. If our program contains errors, the 
 * compiler provides us with a list of error messages, which we need to 
 * record somewhere. To make changes, we have to reenter the editor, 
 * reload our file, and work our way through it, trying to find and correct 
 * all of our mistakes.
*/