sum of two integers

Calculate 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.

题目出处：https://leetcode.com/problems/sum-of-two-integers/

题意：不用+或者-实现加法。

思路：先用a^b得两位相加的结果，再用a&b得到进位，最后加上进位。

代码：

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