资料来源 : Free On-Line Dictionary of Computing

explicit type conversion
     
         (Or "cast" in {C} and elsewhere).  A programming
        construct ({syntax}) to specify that an expression's value
        should be converted to a different type.
     
        For example, in {C}, to convert an {integer} (usually 32 bits)
        to a {char} (usually 8 bits) we might write:
     
        	int i = 42;
        	char *p = &buf;
        	*p = (char) i;
     
        The expression "(char)" (called a "cast") converts i's value
        to char type.  Casts (including this one) are often not
        strictly necessary, due to automatic {coercions} performed by
        the compiler, but can be used to make the conversion obvious
        and to avoid warning messages.
     
        (1999-09-19)