Digital Roots

最新推荐文章于 2020-05-10 23:42:17 发布

wys5

最新推荐文章于 2020-05-10 23:42:17 发布

阅读量136

点赞数

CC 4.0 BY-SA版权

分类专栏： HDU

本文链接：https://blog.youkuaiyun.com/wys5wys/article/details/88044761

HDU 专栏收录该内容

54 篇文章

订阅专栏

本文介绍了一种计算数字根的算法，数字根是指将一个正整数的各位数字相加，直至结果为一位数的过程。文章提供了完整的C语言实现代码，包括输入多个正整数并输出各自数字根的功能。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

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

题目大意：求给出的数各位数字之和，要求和为小于10的数，若和大于10，则再求一次各位数字之和

#include<stdio.h>
#include<string.h>
int sum(int a){
    int b=0;
    while(a>0){
        b+=a%10;
        a/=10;
    }
    return b;
}
int main(){
    char s[10000]={0};
    int a=0,l;
    while(~scanf("%s",&s)){
        l=strlen(s);a=0;
        for(int i=0;i<l;i++){
            a+=(s[i]-'0');
        }
        if(a==0){
            
        }else{
            if(a<10){
                printf("%d\n",a);
            }else{
                while(a>=10){
                    a=sum(a);
                }
                printf("%d\n",a);
            }
        }
        
    }
    
    
    
    
    return 0;
}