Access to the last 2 bytes of an integer

Question

I have a structure that contains an integer and char .. how can I access the last 2 bytes of my int

Answer 1

The term "last byte" in an integer expression is not clear. There are two things you might think about:

• Largest / smallest significant bytes .
• Last bytes when the integer is encoded in either small or large endian form . Endianness is often called byte order.

In the first case, the least significant bytes can be accessed in most languages ​​using (x and 0xffff).

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Answer 2

int i = // ?? get your int somehow
int lastTwoBytes = i & 0x0000FFFF;
int firstTwoBytes = (i >> 16) & 0x0000FFFF; // maybe you really want the first two?

Answer 3

:

union {
    int           i;
    unsigned char bytes[sizeof(int)];
} int_bytes;

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Answer 4

, C/++, - :

struct {
  int myInt;
  char myChar;
} myStruct;

:

lastTwoBytesOfInt = myStruct.myInt & 0x0000FFFF;

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Answer 5

Here's another way to access the upper and lower 16-bits (assuming the short is 16 bits on your system):

unsigned int x = 0x12345678;
cout << hex << ((unsigned short*)&x)[0] << endl; // prints 5678
cout << hex << ((unsigned short*)&x)[1] << endl; // prints 1234

Please note that the result depends on the suitability of your system. http://en.wikipedia.org/wiki/Endianness

Answer 6

In windows, you can use HiWord () / LoWord () to access the first or last 2 bytes.