/* C program to swap bytes/words of integer number.
    How many bytes is 0xff?
    0xff is a number represented in the hexadecimal numeral system (base 16).
    It's composed of two F numbers in hex. As we know,
    F in hex is equivalent to 1111 in the binary numeral system.
    So, 0xff in binary is 11111111.
    

Lets break the format code "%04X" into its separate parts:

The X means that it will print an integer, in hexadecimal, large X for large hexadecimal letters
The 4 means the number will be printed left justified with at least four digits, print spaces if there is less than four digits
The 0 means that if there is less than four digits it will print leading zeroes.

*/

#include <stdio.h>

int main() {
    int val = 0xABCD;

    int ext1 = (val & 0xFF00) >> 8;
    int ext2 = (val & 0x00FF);

    int res = (ext2<<8) + (ext1);

    printf("%X",res);
}

#if 0

int main()
{
    unsigned int data = 0x1234;
    printf("\ndata before swapping : %04X", data);
    //0xff00 = HHHH HHHH 0000 0000

    data = ((data << 8) & 0xff00) | ((data >> 8) & 0x00ff);
    //0010 0011 0100 0000 -> 0010 0011 0000 0000

    printf("\ndata after swapping  : %04X", data);

    return 0;
}

   int d = 0x1234;
   d = ((d<<8) & 0xff00) | ((d>>8) & 0x00ff);
   printf("%x",d);
   
#endif