SOME NEW FEATURES OF C99 (VS. K&R/ANSI C)

 1. The characters // begin a comment that ends at the end of the line.
  
 2. Variable declarations may appear anywhere within a code block; no longer
    must variables be defined at the top of a code block or outside all
    functions.
  
 3. Variable declarations (and initializations) may appear in for loops, as in
      for (int i = 0; i < n; i++) ...

 4. The length of an array may be an expression whose value is not known until
    run-time; no longer must the length of any dimension of an array be known
    at compile-time.
  
 5. The header file stdbool.h (i.e., #include <stdbool.h>) defines type bool
    (meaning boolean) and symbolic constants true and false.
  
 6. Functions must declare a return value; no longer does the type default to
    int if no type is specified.

 7. There is a new type long long which is at least 64 bits and may be either
    signed or unsigned.  The new suffixes "LL" or "ll" (and "ULL" or "ull") are
    used for constants of the new long long type.
  
 8. Function-like macros may accept a variable number of arguments by using
    the ellipsis (...) notation.  For replacement, the variable arguments
    (including the separating commas) are "collected" into one single extra
    argument that may be referenced as __VA_ARGS__ within the macro's
    replacement list, as in
      #define DEBUG(format,...) fprintf(stderr,format,__VA_ARGS__)

 9. The members of a struct may be initialized by name, such as in
      struct {float x, y, z;} s = { .y = 1.0, .x = 3.5, .z = 12.8};

10. The last member of a struct may be an incomplete array type, such as in
      struct {int n; char s[]} string;

11. There are new library functions, such as strdup() and asprintf().
  
12. There are new header files, such as <inttypes.h>.
                                                                CS-223-01/11/20