Swap two nibbles in a byte.md

Swap two nibbles in a byte

METHOD 1

on bitwise and of 15 with number -> number will have only last 4 bits on bitwise and of 240 with number -> number will have only first 4 bits

  for shifting last 4 bit into first 4 bit-> <<4  (right shift)
  for shifting first 4 bit into last 4 bit-> >>4  (left shift)

  then bitwise or

    int swap(int n)
    {
         return ((n&15)<<4) | ((n&240)>>4);
    }

METHOD 2

int swapNibbles(int n) {
        int ans = 0;
        for(int i = 0; i < 8; i++) {
            if((n&1) == 1) {
                if(i < 4)
                    ans = ans + (1 << (4 + i));
                else 
                    ans = ans + (1 << (i - 4));
            }
            n = n >> 1;
        }
        return ans;
    }