剑指 Offer 65. 不用加减乘除做加法

题目链接：
https://leetcode.cn/problems/bu-yong-jia-jian-cheng-chu-zuo-jia-fa-lcof/description/?favorite=xb9nqhhg
代码：

class Solution {
public:
    int add(int a, int b) {
        while(b)
        {
            unsigned int carry=(unsigned int)(a&b)<<1;
            a=a^b;
            b=carry;
        }
        return a;
    }
};