Modulus vs Bit manipulation &
When converting a decimal number to hexadecimal, I always use modulus. There is another way of doing this.
- Mod operation
int digit = num % 16
- Bit operation
int digit = num & 15
查表法
将所有元素临时存起来，建立对应关系，每一次将&15后的值作为索引去查表，就可找到对应的元素。
char[] chs = {'0','1','2','3',
'4','5','6','7',
'8','9','A','B',
'C','D','E','F'};
