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 ret = "";

while(n)
{
ret =(char) ((n-1)%26 + 'A')+ret ;
n = (n-1)/26;

}
return ret;
}
};