This program is system-dependent, it will run correctly on many different systems. Try it on your machine. #if (VAX || PC) #define HEX0 0x6c6c6548 #define HEX1 0x77202c6f #define HEX2 0x646c726f #define HEX3 0x00000a21 #else #define HEX0 0x48656c6c #define HEX1 0x6f2c2077 #define HEX2 0x6f726c64 #define HEX3 0x210a0000 #endif typedef union { char what[16]; long cipher[4]; } mystery; int main(void) { mystery x; x.c...