hdu1013-Digital Roots

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

题意：求各个数位的和，如果大于9，继续处理

#include<iostream>#include<cstdio>#include<cstring>#include<cmath>#include<algorithm>#include<bitset>#include<stdlib.h>using namespace std;int main(){char str[ 1005 ] ;int len , ans , sum ;while( ~scanf( "%s" , str ) ){if( str[ 0 ] == '0' )break ;len = strlen( str ) ;sum = 0 ;while( len-- ){sum += str[ len ] - '0' ;}while( sum > 9 ){ans = 0 ;while( sum ){ans += sum % 10 ;sum /= 10 ;}sum = ans ;}cout << sum << endl ;}return 0 ;}