题解 | #求1+2+3+...+n#

#include <numeric>
class sum 
{
public:
    sum()
    {
        ++_i;
        _ret += _i;
    }
    static int getRet()
    {
        return _ret;
    }
private:
   static int _i;
   static int _ret;
};
int sum::_i = 0;
int sum::_ret = 0;

class Solution {
public:
    int Sum_Solution(int n) {
        sum arr[n];
        return sum::getRet();

    }
};