【leetcode】Excel Sheet Column Title

Given a positive integer, return its corresponding column title as appear in an Excel sheet.

For example:

1 -> A
2 -> B
3 -> C
...
26 -> Z
27 -> AA
28 -> AB

 

class Solution {
public:
    string convertToTitle(int n) {
        if(n<1) return "";
        else
        {
            string ret="";
            while(n)
            {
                n--;
                char c=n%26+'A';
                ret=c+ret;
                n/=26;
            }
              return ret;
        }
    }
};