// refer to// https://leetcode.com/discuss/111582/java-simple-easy-understand-solution-with-explanationclass Solution {public:    int getSum(int a, int b) {        //int tmp_sum = a ^ b; // a xor b        //int tmp_carry = a & b << 1; // (a & b) << 1                while (b != 0) {            int tmp_carry = a & b;            a = a ^ b; // a xor b            b = tmp_carry << 1;        }                return a;    }};