alculate the sum of two integers a and b, but you are not allowed to use the operator + and -.

Example:

Given a = 1 and b = 2, return 3.

 注意：不能使用运算符喽

那我们采用异或移位操作

public class Solution {    public int getSum(int a, int b) {        int sum=0,carry=0;        do{            sum=a^b;            carry=(a&b)<<1;            a=sum;            b=carry;        }while(carry!=0);        return sum;    }}