leetcode 168 Excel Sheet Column Title

class Solution {
public:
    string convertToTitle(int n) {
        string str;
        int div=0,rem=0;
        do {
            div=n/26;rem=n%26;
            if(rem==0) {rem=26;--div;}
            str+=(‘A‘+rem-1);
            n=div;
        }while(div>26);
        if(div) str+=(‘A‘+div-1);
        reverse(str.begin(),str.end());
        return str;
    }
};