371. Sum of Two Integers

https://leetcode.com/problems/sum-of-two-integers/description/

解题思路：
用and operation得到carrry， 用xor operation 得到a，然后对carry左移一位

代码：
class Solution {
public int getSum(int a, int b) {

    if(a == 0) return b;
    while(b != 0){
        int carry = a & b;
        a = a ^ b;
        b = carry << 1;
    }
    return a;    
}

}