Provides alternate spellings.
#include <iso646.h>
The iso646.h header file defines the following eleven macros (on the left) that expand to the corresponding tokens (on the right):
and      && 
and_eq   &= 
bitand   & 
bitor    |
compl    ~ 
not      ! 
not_eq   != 
or       || 
or_eq    |= 
xor      ^
xor_eq   ^=