size_t is the unsigned integer result of the
wchar_t is an integer type of the size of a
wide character constant.
div_t is the structure returned by the
ldiv_t is the structure returned by the
NULL is the value of a null pointer constant.
are values for the exit function to return termination status.
RAND_MAX is the maximum value returned by
the rand function.
MB_CUR_MAX is the maximum number of bytes in
a multibyte character set which cannot be larger than