不用加减乘除做加法

public class Solution {
    public int Add(int num1,int num2) {
        int n1, n2;
        n1 = (num1 & num2) << 1;
        n2 = num1 ^ num2;
        while((n1&n2) != 0) {
            num1 = n1;
            num2 = n2;
            n1 = (num1 & num2) << 1;
            n2 = num1 ^ num2;
        }
        return n1 | n2;
    }
}