hdoj1013

题意：

题意很简单，输入一个数字，循环地把各个十位上的数字相加，直到最后得到的值只有个位就停止并且输出。水题。

代码如下：

#include <iostream>#include <fstream>#include <string>#include <sstream>using namespace std;string int_2_string(int a) {stringstream ss;string ret("");ss << a;ss >> ret;return ret;}string bit_sum(string s) {int sum(0);for (int i = 0, siz = s.size(); i < siz; ++i) {sum += s[i] - '0';}return int_2_string(sum);}int main() {//ifstream cin("in.txt");string s;while (cin >> s) {if ("0" == s) {break;}if (s.size() == 1) {cout << s << endl;continue;}while (s.size() != 1) {s = bit_sum(s);}cout << s << endl;}return 0;}