leetcode[168]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) {
    string s="";
    if(n==0)return s;
    int tmp=n;
    while(tmp)
    {
        tmp--;
        s=char(tmp%26+'A')+s;
        tmp/=26;
    }
    return s;
}
};