题目：

题解：

class Solution {
public:string addStrings(string num1, string num2) {int i = num1.length() - 1, j = num2.length() - 1, add = 0;string ans = "";while (i >= 0 || j >= 0 || add != 0) {int x = i >= 0 ? num1[i] - '0' : 0;int y = j >= 0 ? num2[j] - '0' : 0;int result = x + y + add;ans.push_back('0' + result % 10);add = result / 10;i -= 1;j -= 1;}// 计算完以后的答案需要翻转过来reverse(ans.begin(), ans.end());return ans;}
};