LeetCode 371. Sum of Two Integers

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

思路： 其实就是模拟进位 1.首先最低位相加是要进一的 2.然后在做第二位的运算 3.以此类推，一直到没有进位为止。

代码：

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