题解 | #求1+2+3+...+n#

class Solution
{
    public:

    static int sum;
    static int x;

    Solution()
    {
        sum += x;
        ++x;
    }

    int Sum_Solution(int n) 
    {
        cin>>n;
        Solution a[n-1];
        return sum;
    }

};


int Solution::sum = 0;
int Solution::x = 1;