题解 | #求1+2+3+...+n#

#include <algorithm>
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 a[n];
        return Sum::Getret();
    }
};