【原】LeetCode之Sum of Two Integers

1、题目

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.

Credits:
Special thanks to @fujiaozhu for adding this problem and creating all test cases.

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2、代码实现

public class Solution {
    public int getSum(int a, int b) {
     while(b != 0)  
        {  
            int tmp =(a & b) << 1; 
            //a是每次相加,相当于和
            a = a ^ b;
            //b相当于是进位
            b = tmp;
        }  
        return a;  
     }
}