Excel Sheet Column Title

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;
}