The book is from 1991, almost 20 years ago. There is a lot of outdated information. You should perhaps look for something more recent, that covers C99 and features commonly found on current compilers.
main(){
/* ... */
}
In other places, it puts restrictions that are no longer relevant today. For example, since C99 (and most compilers allowed this long before C99) you can declare variables anywhere inside a block (which is pretty handy), and not just at the beginning of the function.