题解 | #求1+2+3+...+n#

#include <regex>

class Sum
{
public:
    Sum()
     {
        _ret+=_i;
        ++_i;
     }
    static int GetRet()
     {
        return _ret;
     }
private:
     static int _i;
     static int _ret;
};
int Sum:: _i = 1;
int Sum:: _ret = 0;
class Solution
{
public:
    int Sum_Solution(int n) {
       Sum arr[n];
       return Sum::GetRet();
    }
};