Description:

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

Code:

string convertToTitle(int n) {        //这题竟然没有做出来，（n-1)%26（这个式子老是写成n%26-1）与(n-1)/26（这个式子老是搞不清粗是n/26还是n/27)这两个式子一直不清楚        string res = "";          while(n)          {              res = (char)('A' + (n-1)%26) + res;              n = (n-1) / 26;          }          return res;    }