A+B 问题

题目

源码

public class Solution {
    /**
     * @param a: An integer
     * @param b: An integer
     * @return: The sum of a and b 
     */
    public int aplusb(int a, int b) {
        // write your code here
        // int sum;
        // int carry;
        // while (b!=0){
        //     sum=a^b;
        //     carry=(a&b)<<1;
        //     a=sum;
        //     b=carry;
        // }
        // return a;
        int sum;
        int carry;
        do{
            sum=a^b;
            carry=(a&b)<<1;
            a=sum;
            b=carry;
        }while (carry!=0);
        return sum;
    }
}