Count and Say

class Solution {
public:
    string countAndSay(int n) {
        int k=0,i,j;
        string s1,s2;
        s1+='1';

        for(i=1;i<n;i++)
        {
            //cout<<s1<<endl;
            s2.clear();
            int sum=0,c=-3;
            for(j=0;j<s1.size();j++)
            {
                if(j!=0 && s1[j]!=c)
                {
                    s2+=sum+'0';
                    s2+=c;
                    sum=0;
                }
                c=s1[j];
                sum++;
            }
            s2+=sum+'0';
            s2+=c;
            s1=s2;
        }
        return s1;
    }
};