zju 1115 Digital roots 数字根

#include <iostream>
#include <string>
using namespace std;
int main()
{
   string n;
 while(cin>>n,n!="0")
{
    int s=0,l=n.length();
    
  for(int i=0;i<l;i++)    s+=n[i]-'0';
  
while(s>9)   s=s/10+s%10;
  cout<<s<<endl;
}
return 0;
}

#include <iostream>
#include <string>
using namespace std;
int main()
{
   string n;
 while(cin>>n,n!="0")
{
    int s=0,l=n.length();
   
  for(int i=0;i<l;i++)    s+=n[i]-'0';
 
while(s>9)   s=s/10+s%10;
  cout<<s<<endl;
}
return 0;
}