题解 | #求1+2+3+...+n#

class sum
{
public:
    //friend int Sum_Solution(int n);
    sum()
    {
        b += a;
        ++a;
    }
   static int Getcount()
    {
        return b;
    }
private:
    static  int a;
    static int b;
};
int sum::a = 1;
int sum::b = 0;
class Solution {
public:
    int Sum_Solution(int n) {
        sum a[n];
        return sum::Getcount();
    }
};