fjnu 1095 Digital Roots

最新推荐文章于 2025-08-12 18:25:18 发布

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本文介绍了一种计算任意正整数的数字根的方法。通过不断累加整数的各位数字直至得到单个数字的过程来确定其数字根。文章还提供了一个使用C++编写的程序示例，用于读取一系列正整数并输出每个整数对应的数字根。

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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

KEY:没什么难度，认真看看题目；

Source:

#include<iostream>
using namespace std;

int root(int n)
{
	int sum=0;
	if(n<10) return n;
	else
	{
		while(1)
		{
			while(n!=0)
			{
				sum+=n%10;
				n=n/10;
			}
			if(sum<10) return sum;
			else 
			{
				n=sum;
				sum=0;
			}
		}
	}
}

int input()
{
	char ch[100000];
	cin>>ch;
	int n=0;
    for(int i=0;ch[i]!='/0';i++)
	{
		n+=ch[i]-48;
	}
	return n;
}

int main()
{  
	int n;
	n=input();
	while(n!=0)
	{
		cout<<root(n)<<endl;
		n=input();		
	}
}