leetcode 202. Happy Number

#include<set>
class Solution {
public:
    bool isHappy(int n) {
        set<int> visited;
        visited.insert(n);
        int sum = n;
        while(sum!=1)
        {
            n = sum;
            sum = 0;
            while(n>0)
             {
                 sum += (n %10)*(n%10);
            
                 n = n/10;
                 
             }
            // cout<<sum<<endl;
            set<int>::iterator iter;
	        iter=visited.find(sum);
            if(iter!=visited.end())return false;
            else visited.insert(sum);
           
        }
        return true;
    }
};