题解 | #求1+2+3+...+n#

class A 
{
public:
     A()
     {
         _sum+=_i;
        _i++;
     }
    static int GetSum() 
    {     
        return _sum; 
    }
private:
    static int _i;
    static int _sum;
};
int A::_i=1;
int A::_sum=0;
class Solution {
public:
    int Sum_Solution(int n) {
        A a[n];
        return A::GetSum();
    }
};