剑指offer——75不用加减乘除做加法

 1 class Solution {
 2 public:
 3     int Add(int num1, int num2){
 4         int sum, carry;
 5         while (num2 != 0) {
 6             sum = num1 ^ num2;//只现相加，不进位
 7             carry = (num1&num2) << 1;//记录进位
 8             num1 = sum;
 9             num2 = carry;
10         }
11         return num1;
12     }
13 };