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 

递归的方法

class Solution {
public:
    string convertToTitle(int n) {
        if(n == 0)  return "";

        return convertToTitle((n-1)/26) + char((n - 1) % 26 + 'A');
    }
};

迭代的方法

class Solution {
public:
    string convertToTitle(int n) {
        string res;

        while(n){
            res = char((n - 1) % 26 + 'A') + res;
            n = (n - 1)/26;
        }
        return res;
    }
};```c++