BYTE bytes1[4] = {0x00,0x10,0x40,0x00};    //创建4字节的字节数组  注意：字节是逆序的

BYTE bytes2[4] = {0x05,0x20,0x40,0x00};    

DWORD b1 = *(DWORD *)bytes1;        //先将bytes1转化成(DWORD *)的指针  再用取值符 * 获得四个字节的值

DWORD b2 = *(DWORD *)bytes2;

DWORD result = b1-b2;        //进行二进制计算

printf("%X-%X=%X",b1,b2,result);