(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) {
		char c;
		string result;
		if(n < 1) return "";
		while(n)
		{
			n--;
			c = n%26 + 'A';
			result = c + result;
			n = n/26;
		}
		return result;	
    }
};