Swap two nibbles in a byte

#include <stdio.h>

 

unsigned char swapNibbles(unsigned char x)

{

    return ( (x & 0x0F)<<4 | (x & 0xF0)>>4 );

}

 

int main()

{

    unsigned char x = 100;

    printf("%u", swapNibbles(x));

    return 0;

}