[C++]Excel Sheet Column Title

leetcode 原题链接：https://leetcode.com/problems/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 

实现代码：

<span style="font-size:14px;">class Solution{public:string convertToTitle(int n){if (n <= 0)return NULL;string ans = "";while (n-- != 0){int temp = n % 26;ans = (char)('A' + temp) + ans;n /= 26;}return ans;}};</span>