HDU 1013 Digital Roots（to_string的具体运用）

传送门：http://acm.hdu.edu.cn/showproblem.php?pid=1013

Digital Roots

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 90108    Accepted Submission(s): 28027

Problem Description

The digital root of a positive integer is found by summing the digits of the integer. If the resulting value is a single digit then that digit is the digital root. If the resulting value contains two or more digits, those digits are summed and the process is repeated. This is continued as long as necessary to obtain a single digit.

For example, consider the positive integer 24. Adding the 2 and the 4 yields a value of 6. Since 6 is a single digit, 6 is the digital root of 24. Now consider the positive integer 39. Adding the 3 and the 9 yields 12. Since 12 is not a single digit, the process must be repeated. Adding the 1 and the 2 yeilds 3, a single digit and also the digital root of 39.

 

Input

The input file will contain a list of positive integers, one per line. The end of the input will be indicated by an integer value of zero.

 

Output

For each integer in the input, output its digital root on a separate line of the output.

 

Sample Input

24

39

0

 

Sample Output

6

3

 

 

分析：

这个题有点坑，不能用int输入，也不能用long long 输入

得用字符串

应该是输入太大了

有点编译器可能无法识别to_string，需要下载补丁。。。

比如codeblocks

code：

#include<bits/stdc++.h>
#include<string.h>
using namespace std;
typedef long long LL;
int main()
{
    string s;
    LL sum;
    while(cin>>s)
    {
        if(s=="0")
            break;
        while(s.size()>1)//当size==1的时候，就是答案
        {
            sum=0;
            for(int i=0;i<s.size();i++)
            {
                sum+=(s[i]-'0');//累加
            }
            s=to_string(sum);//转化成字符串
        }
        cout<<s<<endl;
    }
    return 0;
}